diff --git a/src/components/Note/AsciidocArticle/AsciidocArticle.tsx b/src/components/Note/AsciidocArticle/AsciidocArticle.tsx
index 83df540b..ab847e61 100644
--- a/src/components/Note/AsciidocArticle/AsciidocArticle.tsx
+++ b/src/components/Note/AsciidocArticle/AsciidocArticle.tsx
@@ -350,12 +350,15 @@ export default function AsciidocArticle({
   event,
   className,
   hideImagesAndInfo = false,
+  hideTitle = false,
   parentImageUrl,
   footnotesContainerId
 }: {
   event: Event
   className?: string
   hideImagesAndInfo?: boolean
+  /** Suppress title headings (e.g. when a parent renders the section title). */
+  hideTitle?: boolean
   parentImageUrl?: string
   footnotesContainerId?: string
 }) {
@@ -1956,8 +1959,8 @@ export default function AsciidocArticle({
       `}</style>
       <div className={`prose prose-zinc max-w-none dark:prose-invert break-words overflow-wrap-anywhere ${className || ''}`}>
         {/* Metadata */}
-        {!hideImagesAndInfo && metadata.title && <h1 className="break-words">{metadata.title}</h1>}
-        {!hideImagesAndInfo && !metadata.title && isBookstrEvent && (
+        {!hideTitle && !hideImagesAndInfo && metadata.title && <h1 className="break-words">{metadata.title}</h1>}
+        {!hideTitle && !hideImagesAndInfo && !metadata.title && isBookstrEvent && (
           <h1 className="break-words">
             {bookMetadata.book
               ? bookMetadata.book
@@ -1984,10 +1987,10 @@ export default function AsciidocArticle({
             <p className="break-words">{metadata.summary}</p>
           </blockquote>
         )}
-        {hideImagesAndInfo && metadata.title && (
+        {!hideTitle && hideImagesAndInfo && metadata.title && (
           <h2 className="text-2xl font-bold mb-4 leading-tight break-words">{metadata.title}</h2>
         )}
-        {hideImagesAndInfo && !metadata.title && isBookstrEvent && (
+        {!hideTitle && hideImagesAndInfo && !metadata.title && isBookstrEvent && (
           <h2 className="text-2xl font-bold mb-4 leading-tight break-words">
             {bookMetadata.book
               ? bookMetadata.book
diff --git a/src/components/Note/PublicationIndexBody.tsx b/src/components/Note/PublicationIndexBody.tsx
new file mode 100644
index 00000000..87c5b0a7
--- /dev/null
+++ b/src/components/Note/PublicationIndexBody.tsx
@@ -0,0 +1,224 @@
+import AsciidocArticle from '@/components/Note/AsciidocArticle/AsciidocArticle'
+import MarkdownArticle from '@/components/Note/MarkdownArticle/MarkdownArticle'
+import NoteOptions from '@/components/NoteOptions'
+import { ExtendedKind, FAST_READ_RELAY_URLS } from '@/constants'
+import { orderedPublicationRefsFromIndex } from '@/lib/publication-asciidoc-assembler'
+import { fetchPublicationTreeForExport } from '@/lib/publication-export'
+import {
+  buildPublicationSectionTree,
+  flattenPublicationSectionTreeForToc,
+  type PublicationSectionTreeNode
+} from '@/lib/publication-section-tree'
+import { normalizeAnyRelayUrl } from '@/lib/url'
+import { cn } from '@/lib/utils'
+import { useCurrentRelays } from '@/providers/CurrentRelaysProvider'
+import { useFavoriteRelays } from '@/providers/FavoriteRelaysProvider'
+import { BookOpen, Loader2 } from 'lucide-react'
+import { Event, kinds } from 'nostr-tools'
+import { useCallback, useEffect, useMemo, useState } from 'react'
+import { useTranslation } from 'react-i18next'
+
+const ASCIIDOC_CONTENT_KINDS = new Set<number>([
+  ExtendedKind.PUBLICATION_CONTENT,
+  ExtendedKind.WIKI_ARTICLE
+])
+
+type HeadingTag = 'h2' | 'h3' | 'h4' | 'h5' | 'h6'
+
+function SectionHeadingRow({
+  title,
+  event,
+  Heading
+}: {
+  title: string
+  event?: Event
+  Heading: HeadingTag
+}) {
+  return (
+    <div className="flex min-w-0 items-start gap-1">
+      <Heading className="min-w-0 flex-1 text-base font-semibold break-words text-foreground">
+        {title}
+      </Heading>
+      {event ? <NoteOptions event={event} className="shrink-0 -mr-1 -mt-0.5" /> : null}
+    </div>
+  )
+}
+
+function SectionContent({ event }: { event: Event }) {
+  if (ASCIIDOC_CONTENT_KINDS.has(event.kind)) {
+    return (
+      <AsciidocArticle className="mt-2" event={event} hideImagesAndInfo hideTitle />
+    )
+  }
+  if (event.kind === kinds.LongFormArticle) {
+    return <MarkdownArticle className="mt-2" event={event} hideMetadata />
+  }
+  if ((event.content ?? '').trim()) {
+    return (
+      <div className="mt-2 whitespace-pre-wrap break-words text-base text-foreground">
+        {event.content}
+      </div>
+    )
+  }
+  return null
+}
+
+function PublicationSectionNodeView({ node }: { node: PublicationSectionTreeNode }) {
+  const Heading = `h${Math.min(6, node.depth + 2)}` as HeadingTag
+
+  return (
+    <section id={node.sectionId} className="scroll-mt-24 mt-4 first:mt-0">
+      <SectionHeadingRow title={node.title} event={node.event} Heading={Heading} />
+      {node.isPublicationBranch && node.event?.content.trim() ? (
+        <div className="mt-2 whitespace-pre-wrap break-words text-muted-foreground">
+          {node.event.content.trim()}
+        </div>
+      ) : null}
+      {node.isPublicationBranch ? (
+        node.children.length > 0 ? (
+          <div className="mt-4 border-l border-border pl-4">
+            {node.children.map((child) => (
+              <PublicationSectionNodeView key={child.path} node={child} />
+            ))}
+          </div>
+        ) : null
+      ) : node.event ? (
+        <SectionContent event={node.event} />
+      ) : null}
+    </section>
+  )
+}
+
+function PublicationTableOfContents({
+  entries,
+  className
+}: {
+  entries: ReturnType<typeof flattenPublicationSectionTreeForToc>
+  className?: string
+}) {
+  const { t } = useTranslation()
+
+  const scrollToSection = useCallback((id: string) => {
+    document.getElementById(id)?.scrollIntoView({ behavior: 'smooth', block: 'start' })
+  }, [])
+
+  if (entries.length === 0) return null
+
+  return (
+    <nav
+      className={cn('rounded-lg border border-border bg-muted/20 p-3', className)}
+      aria-label={t('Publication table of contents')}
+    >
+      <div className="mb-2 flex items-center gap-2 text-sm font-medium text-foreground">
+        <BookOpen className="size-4 shrink-0 text-muted-foreground" aria-hidden />
+        {t('Publication table of contents')}
+      </div>
+      <ol className="max-h-64 space-y-0.5 overflow-y-auto text-sm">
+        {entries.map((entry) => (
+          <li key={entry.path}>
+            <button
+              type="button"
+              className="w-full min-w-0 rounded py-1 pr-2 text-left text-muted-foreground hover:bg-accent hover:text-accent-foreground"
+              style={{ paddingLeft: `${8 + entry.depth * 14}px` }}
+              onClick={() => scrollToSection(entry.id)}
+            >
+              <span className="break-words">{entry.title}</span>
+            </button>
+          </li>
+        ))}
+      </ol>
+    </nav>
+  )
+}
+
+export default function PublicationIndexBody({
+  event,
+  className
+}: {
+  event: Event
+  className?: string
+}) {
+  const { t } = useTranslation()
+  const { relayUrls: currentBrowsingRelayUrls } = useCurrentRelays()
+  const { favoriteRelays } = useFavoriteRelays()
+  const relayUrls = useMemo(
+    () =>
+      Array.from(
+        new Set([
+          ...currentBrowsingRelayUrls.map((url) => normalizeAnyRelayUrl(url) || url),
+          ...favoriteRelays.map((url) => normalizeAnyRelayUrl(url) || url),
+          ...FAST_READ_RELAY_URLS.map((url) => normalizeAnyRelayUrl(url) || url)
+        ])
+      ).filter(Boolean) as string[],
+    [currentBrowsingRelayUrls, favoriteRelays]
+  )
+
+  const [fetched, setFetched] = useState<Map<string, Event> | null>(null)
+  const [loading, setLoading] = useState(true)
+  const [error, setError] = useState<string | null>(null)
+
+  useEffect(() => {
+    let cancelled = false
+    setLoading(true)
+    setError(null)
+    setFetched(null)
+
+    fetchPublicationTreeForExport(event, relayUrls)
+      .then((tree) => {
+        if (cancelled) return
+        setFetched(tree)
+      })
+      .catch((err: unknown) => {
+        if (cancelled) return
+        setError(err instanceof Error ? err.message : String(err))
+      })
+      .finally(() => {
+        if (!cancelled) setLoading(false)
+      })
+
+    return () => {
+      cancelled = true
+    }
+  }, [event, relayUrls])
+
+  const sectionTree = useMemo(
+    () => (fetched ? buildPublicationSectionTree(event, fetched) : []),
+    [event, fetched]
+  )
+
+  const tocEntries = useMemo(
+    () => flattenPublicationSectionTreeForToc(sectionTree),
+    [sectionTree]
+  )
+
+  const hasRefs = orderedPublicationRefsFromIndex(event).length > 0
+  if (!hasRefs) return null
+
+  return (
+    <div className={cn('min-w-0 space-y-4', className)}>
+      {loading ? (
+        <div className="flex items-center gap-2 rounded-lg border border-border bg-muted/20 p-3 text-sm text-muted-foreground">
+          <Loader2 className="size-4 shrink-0 animate-spin" aria-hidden />
+          {t('Publication contents loading')}
+        </div>
+      ) : null}
+
+      {error ? (
+        <p className="text-sm text-destructive">
+          {t('Publication contents load failed')}: {error}
+        </p>
+      ) : null}
+
+      {fetched && !error ? (
+        <>
+          <PublicationTableOfContents entries={tocEntries} />
+          <div>
+            {sectionTree.map((node) => (
+              <PublicationSectionNodeView key={node.path} node={node} />
+            ))}
+          </div>
+        </>
+      ) : null}
+    </div>
+  )
+}
diff --git a/src/components/Note/PublicationIndexMetadata.tsx b/src/components/Note/PublicationIndexMetadata.tsx
index 1e8312cd..93278373 100644
--- a/src/components/Note/PublicationIndexMetadata.tsx
+++ b/src/components/Note/PublicationIndexMetadata.tsx
@@ -7,13 +7,14 @@ import { toNoteList } from '@/lib/link'
 import { cn } from '@/lib/utils'
 import { useSecondaryPageOptional } from '@/PageManager'
 import { useShouldAutoLoadMedia } from '@/hooks/useShouldAutoLoadMedia'
-import { BookOpen, ExternalLink } from 'lucide-react'
+import { ExternalLink } from 'lucide-react'
 import { Event, kinds } from 'nostr-tools'
 import { useMemo } from 'react'
 import { useTranslation } from 'react-i18next'
 import PublicationCoverFallback from './PublicationCoverFallback'
 import PublicationCoverImage from './PublicationCoverImage'
 import PublicationBooklistButton from './PublicationBooklistButton'
+import PublicationIndexBody from './PublicationIndexBody'
 
 function formatAuthorLine(authors: PublicationAuthor[]): string {
   if (authors.length === 0) return ''
@@ -201,26 +202,7 @@ export default function PublicationIndexMetadata({
         </div>
       ) : null}
 
-      {isFull && metadata.sections.length > 0 ? (
-        <div className="rounded-lg border border-border bg-muted/20 p-3">
-          <div className="mb-2 flex items-center gap-2 text-sm font-medium text-foreground">
-            <BookOpen className="size-4 shrink-0 text-muted-foreground" aria-hidden />
-            {t('Publication table of contents')}
-          </div>
-          <ol className="max-h-64 space-y-1 overflow-y-auto text-sm text-muted-foreground">
-            {metadata.sections.map((section, index) => (
-              <li key={`${section.coordinate}-${index}`} className="flex min-w-0 gap-2">
-                <span className="shrink-0 tabular-nums text-muted-foreground/80">{index + 1}.</span>
-                <span className="min-w-0 break-words">
-                  {section.label ||
-                    section.coordinate.split(':').pop()?.replace(/-/g, ' ') ||
-                    section.coordinate}
-                </span>
-              </li>
-            ))}
-          </ol>
-        </div>
-      ) : null}
+      {isFull && metadata.sectionCount > 0 ? <PublicationIndexBody event={event} /> : null}
     </div>
   )
 }
diff --git a/src/i18n/locales/de.ts b/src/i18n/locales/de.ts
index c4c70a7b..07e2bf5b 100644
--- a/src/i18n/locales/de.ts
+++ b/src/i18n/locales/de.ts
@@ -1671,6 +1671,8 @@ export default {
     'Publication sections_other': '{{count}} Abschnitte',
     'Publication released': 'Veröffentlicht {{date}}',
     'Publication table of contents': 'Inhalt',
+    'Publication contents loading': 'Inhalt wird geladen…',
+    'Publication contents load failed': 'Inhalt konnte nicht geladen werden',
     'libraryIndexCache.sectionTitle': 'Bibliotheks-Publikationsindex',
     'libraryIndexCache.sectionBlurb':
       'Zwischengespeicherte Kind-30040-Index-Events für den Bibliotheks-Tab. Beim Leeren wird nur der Entdeckungslisten-Cache entfernt — geöffnete Publikationen bleiben im Lese-Cache.',
diff --git a/src/i18n/locales/en.ts b/src/i18n/locales/en.ts
index 11409506..3cac94e1 100644
--- a/src/i18n/locales/en.ts
+++ b/src/i18n/locales/en.ts
@@ -1702,6 +1702,8 @@ export default {
     'Publication sections_other': '{{count}} sections',
     'Publication released': 'Released {{date}}',
     'Publication table of contents': 'Contents',
+    'Publication contents loading': 'Loading contents…',
+    'Publication contents load failed': 'Could not load publication contents',
     'libraryIndexCache.sectionTitle': 'Library publication index',
     'libraryIndexCache.sectionBlurb':
       'Cached kind-30040 index events used to populate the Library tab. Clearing this only removes the discovery list cache—not publications you have opened for reading.',
diff --git a/src/lib/event-metadata.ts b/src/lib/event-metadata.ts
index dc75c393..1a034f55 100644
--- a/src/lib/event-metadata.ts
+++ b/src/lib/event-metadata.ts
@@ -717,10 +717,16 @@ export function getPublicationIndexMetadataFromEvent(event: Event): PublicationI
     } else if (name === 'l' && !language) {
       language = value
     } else if (name === 'a') {
-      const label = tag[3]?.trim() || tag[2]?.trim()
+      const label = tag[3]?.trim()
       sections.push({
         coordinate: value,
-        label: label && !label.startsWith('wss://') && !label.startsWith('ws://') ? label : undefined
+        label:
+          label &&
+          !label.startsWith('wss://') &&
+          !label.startsWith('ws://') &&
+          !/^[0-9a-f]{64}$/i.test(label)
+            ? label
+            : undefined
       })
     }
   }
diff --git a/src/lib/publication-asciidoc-assembler.ts b/src/lib/publication-asciidoc-assembler.ts
index 084505ee..f6651fd4 100644
--- a/src/lib/publication-asciidoc-assembler.ts
+++ b/src/lib/publication-asciidoc-assembler.ts
@@ -55,6 +55,7 @@ function authorFromMetadata(metadata: PublicationIndexMetadata, pubkey: string):
 /** Ordered `a` / `e` refs from index tags (NKBIP-01 section order). */
 export function orderedPublicationRefsFromIndex(event: Event): PublicationSectionRef[] {
   const refs: PublicationSectionRef[] = []
+  let tagOrder = 0
   for (const tag of event.tags) {
     const name = (tag[0] || '').trim().toLowerCase()
     if (name === 'a' && tag[1]) {
@@ -66,10 +67,11 @@ export function orderedPublicationRefsFromIndex(event: Event): PublicationSectio
         kind: parsed.kind,
         pubkey: parsed.pubkey,
         identifier: parsed.identifier,
-        relay: tag[2]
+        relay: tag[2],
+        tagOrder: tagOrder++
       })
     } else if (name === 'e' && tag[1]) {
-      refs.push({ type: 'e', eventId: tag[1], relay: tag[2] })
+      refs.push({ type: 'e', eventId: tag[1], relay: tag[2], tagOrder: tagOrder++ })
     }
   }
   return refs
diff --git a/src/lib/publication-section-fetch.ts b/src/lib/publication-section-fetch.ts
index 11e9d8cc..4e8d18f5 100644
--- a/src/lib/publication-section-fetch.ts
+++ b/src/lib/publication-section-fetch.ts
@@ -15,6 +15,8 @@ export type PublicationSectionRef = {
   pubkey?: string
   identifier?: string
   relay?: string
+  /** Zero-based order among `a` / `e` refs in the index event tag list. */
+  tagOrder?: number
 }
 
 export function publicationRefKey(ref: PublicationSectionRef): string {
diff --git a/src/lib/publication-section-tree.test.ts b/src/lib/publication-section-tree.test.ts
new file mode 100644
index 00000000..6ef1ecc4
--- /dev/null
+++ b/src/lib/publication-section-tree.test.ts
@@ -0,0 +1,136 @@
+import { describe, expect, it } from 'vitest'
+import { ExtendedKind } from '@/constants'
+import { orderedPublicationRefsFromIndex } from '@/lib/publication-asciidoc-assembler'
+import {
+  buildPublicationSectionTree,
+  flattenPublicationSectionTreeForToc
+} from '@/lib/publication-section-tree'
+import type { Event } from 'nostr-tools'
+
+const PK = 'a'.repeat(64)
+
+function indexEvent(tags: string[][], id: string): Event {
+  return {
+    id,
+    kind: ExtendedKind.PUBLICATION,
+    pubkey: PK,
+    created_at: 100,
+    content: '',
+    tags,
+    sig: 'c'.repeat(128)
+  }
+}
+
+function sectionEvent(d: string, title: string, id: string): Event {
+  return {
+    id,
+    kind: ExtendedKind.PUBLICATION_CONTENT,
+    pubkey: PK,
+    created_at: 50,
+    content: `Body of ${title}`,
+    tags: [['d', d], ['title', title]],
+    sig: 'd'.repeat(128)
+  }
+}
+
+describe('buildPublicationSectionTree', () => {
+  it('preserves a-tag order from each 30040 index', () => {
+    const c1 = `30041:${PK}:chapter-1`
+    const c2 = `30041:${PK}:chapter-2`
+    const c3 = `30041:${PK}:chapter-3`
+    const root = indexEvent(
+      [
+        ['d', 'book'],
+        ['title', 'Book'],
+        ['a', c3, '', 'Three'],
+        ['t', 'ignored'],
+        ['a', c1, '', 'One'],
+        ['a', c2, '', 'Two']
+      ],
+      'root-id'
+    )
+    const ch1 = sectionEvent('chapter-1', 'Chapter One', 'ch1-id')
+    const ch2 = sectionEvent('chapter-2', 'Chapter Two', 'ch2-id')
+    const ch3 = sectionEvent('chapter-3', 'Chapter Three', 'ch3-id')
+    const fetched = new Map<string, Event>([
+      [c1, ch1],
+      [c2, ch2],
+      [c3, ch3]
+    ])
+
+    const tree = buildPublicationSectionTree(root, fetched)
+    expect(tree.map((n) => n.title)).toEqual(['Chapter Three', 'Chapter One', 'Chapter Two'])
+    expect(tree.map((n) => n.tagOrder)).toEqual([0, 1, 2])
+  })
+
+  it('keeps TOC and content traversal in the same order', () => {
+    const part = `30040:${PK}:part-1`
+    const c1 = `30041:${PK}:chapter-1`
+    const c2 = `30041:${PK}:chapter-2`
+    const root = indexEvent(
+      [
+        ['d', 'book'],
+        ['title', 'Book'],
+        ['a', part],
+        ['a', c2],
+        ['a', c1]
+      ],
+      'root-id'
+    )
+    const partIndex = indexEvent(
+      [
+        ['d', 'part-1'],
+        ['title', 'Part One'],
+        ['a', c1, '', 'First'],
+        ['a', c2, '', 'Second']
+      ],
+      'part-id'
+    )
+    const ch1 = sectionEvent('chapter-1', 'Chapter One', 'ch1-id')
+    const ch2 = sectionEvent('chapter-2', 'Chapter Two', 'ch2-id')
+    const fetched = new Map<string, Event>([
+      [part, partIndex],
+      [c1, ch1],
+      [c2, ch2]
+    ])
+
+    const tree = buildPublicationSectionTree(root, fetched)
+    const toc = flattenPublicationSectionTreeForToc(tree)
+
+    expect(toc.map((e) => e.title)).toEqual([
+      'Part One',
+      'Chapter One',
+      'Chapter Two',
+      'Chapter Two',
+      'Chapter One'
+    ])
+
+    const contentOrder = (function walk(nodes: typeof tree): string[] {
+      const titles: string[] = []
+      for (const node of nodes) {
+        titles.push(node.title)
+        if (node.children.length > 0) titles.push(...walk(node.children))
+      }
+      return titles
+    })(tree)
+
+    expect(contentOrder).toEqual(toc.map((e) => e.title))
+  })
+
+  it('orderedPublicationRefsFromIndex assigns tagOrder in tag-list sequence', () => {
+    const root = indexEvent(
+      [
+        ['d', 'book'],
+        ['title', 'Book'],
+        ['a', `30041:${PK}:b`],
+        ['summary', 'x'],
+        ['a', `30041:${PK}:a`],
+        ['e', 'f'.repeat(64)]
+      ],
+      'root-id'
+    )
+    const refs = orderedPublicationRefsFromIndex(root)
+    expect(refs.map((r) => r.tagOrder)).toEqual([0, 1, 2])
+    expect(refs.map((r) => r.type)).toEqual(['a', 'a', 'e'])
+  })
+})
diff --git a/src/lib/publication-section-tree.ts b/src/lib/publication-section-tree.ts
new file mode 100644
index 00000000..17cb6403
--- /dev/null
+++ b/src/lib/publication-section-tree.ts
@@ -0,0 +1,181 @@
+import { ExtendedKind } from '@/constants'
+import { eventTagAddress } from '@/lib/publication-index'
+import { orderedPublicationRefsFromIndex } from '@/lib/publication-asciidoc-assembler'
+import {
+  publicationRefKey,
+  type PublicationSectionRef
+} from '@/lib/publication-section-fetch'
+import type { Event } from 'nostr-tools'
+
+const MAX_NEST_DEPTH = 8
+
+export type PublicationSectionTreeNode = {
+  ref: PublicationSectionRef
+  event?: Event
+  indexEvent: Event
+  depth: number
+  tagOrder: number
+  path: string
+  sectionId: string
+  title: string
+  isPublicationBranch: boolean
+  children: PublicationSectionTreeNode[]
+}
+
+export type PublicationTocEntry = {
+  id: string
+  title: string
+  depth: number
+  tagOrder: number
+  path: string
+}
+
+function tagValue(event: Event, name: string): string | undefined {
+  for (const tag of event.tags) {
+    if ((tag[0] || '').trim().toLowerCase() !== name) continue
+    const value = tag[1]?.trim()
+    if (value) return value
+  }
+  return undefined
+}
+
+function isHex64(value: string): boolean {
+  return /^[0-9a-f]{64}$/i.test(value)
+}
+
+function sectionLabelMapFromIndex(index: Event): Map<string, string> {
+  const map = new Map<string, string>()
+  for (const tag of index.tags) {
+    if (tag[0] !== 'a' || !tag[1]) continue
+    const label = tag[3]?.trim()
+    if (!label || label.startsWith('wss://') || label.startsWith('ws://') || isHex64(label)) continue
+    map.set(tag[1], label)
+  }
+  return map
+}
+
+function coordinateForRef(ref: PublicationSectionRef, event?: Event): string | undefined {
+  if (ref.coordinate?.trim()) return ref.coordinate.trim()
+  if (event) return eventTagAddress(event) ?? undefined
+  return undefined
+}
+
+function humanizeIdentifier(identifier: string): string | undefined {
+  if (!identifier || isHex64(identifier)) return undefined
+  return identifier.replace(/-/g, ' ')
+}
+
+export function sectionTitle(
+  ref: PublicationSectionRef,
+  event: Event | undefined,
+  labelMap: Map<string, string>
+): string {
+  if (event) {
+    const title = tagValue(event, 'title')
+    if (title) return title
+    const dTag = tagValue(event, 'd')
+    const humanizedD = dTag ? humanizeIdentifier(dTag) : undefined
+    if (humanizedD) return humanizedD
+  }
+
+  const coordinate = coordinateForRef(ref, event)
+  if (coordinate) {
+    const label = labelMap.get(coordinate)
+    if (label) return label
+  }
+
+  const identifier =
+    ref.identifier ??
+    (coordinate ? coordinate.split(':').slice(2).join(':') : undefined)
+  const humanized = identifier ? humanizeIdentifier(identifier) : undefined
+  if (humanized) return humanized
+
+  return 'Section'
+}
+
+function sectionAnchorId(path: string, refKey: string): string {
+  const slug = refKey
+    .toLowerCase()
+    .replace(/[^a-z0-9]+/g, '-')
+    .replace(/^-+|-+$/g, '')
+    .slice(0, 80)
+  return slug ? `pub-section-${path.replace(/\//g, '-')}-${slug}` : `pub-section-${path.replace(/\//g, '-')}`
+}
+
+function resolveRefEvent(
+  ref: PublicationSectionRef,
+  fetched: Map<string, Event>
+): Event | undefined {
+  return fetched.get(publicationRefKey(ref))
+}
+
+function isPublicationBranchRef(ref: PublicationSectionRef): boolean {
+  if (ref.type !== 'a' || !ref.coordinate) return false
+  const kind = ref.kind ?? parseInt(ref.coordinate.split(':')[0], 10)
+  return kind === ExtendedKind.PUBLICATION
+}
+
+/**
+ * Build a section tree mirroring each index event's `a` / `e` tag order.
+ * Sibling order matches `orderedPublicationRefsFromIndex`; children follow depth-first.
+ */
+export function buildPublicationSectionTree(
+  indexEvent: Event,
+  fetched: Map<string, Event>,
+  depth = 0,
+  pathPrefix = ''
+): PublicationSectionTreeNode[] {
+  if (depth > MAX_NEST_DEPTH) return []
+
+  const labelMap = sectionLabelMapFromIndex(indexEvent)
+  const refs = orderedPublicationRefsFromIndex(indexEvent)
+  const nodes: PublicationSectionTreeNode[] = []
+
+  for (const ref of refs) {
+    const tagOrder = ref.tagOrder ?? nodes.length
+    const event = resolveRefEvent(ref, fetched)
+    const coordinate = coordinateForRef(ref, event)
+    const refKey = coordinate || publicationRefKey(ref)
+    const path = pathPrefix ? `${pathPrefix}/${tagOrder}` : String(tagOrder)
+    const isPublicationBranch = isPublicationBranchRef(ref)
+    const children =
+      isPublicationBranch && event
+        ? buildPublicationSectionTree(event, fetched, depth + 1, path)
+        : []
+
+    nodes.push({
+      ref,
+      event,
+      indexEvent,
+      depth,
+      tagOrder,
+      path,
+      sectionId: sectionAnchorId(path, refKey),
+      title: sectionTitle(ref, event, labelMap),
+      isPublicationBranch,
+      children
+    })
+  }
+
+  return nodes
+}
+
+/** Depth-first flattening preserves the same order as {@link buildPublicationSectionTree}. */
+export function flattenPublicationSectionTreeForToc(
+  nodes: PublicationSectionTreeNode[]
+): PublicationTocEntry[] {
+  const entries: PublicationTocEntry[] = []
+  for (const node of nodes) {
+    entries.push({
+      id: node.sectionId,
+      title: node.title,
+      depth: node.depth,
+      tagOrder: node.tagOrder,
+      path: node.path
+    })
+    if (node.children.length > 0) {
+      entries.push(...flattenPublicationSectionTreeForToc(node.children))
+    }
+  }
+  return entries
+}