diff --git a/crates/chunkmd/src/pages.rs b/crates/chunkmd/src/pages.rs
index ff315c6..eca70da 100644
--- a/crates/chunkmd/src/pages.rs
+++ b/crates/chunkmd/src/pages.rs
@@ -4,6 +4,7 @@
 //! and chapter boundaries as headings. Both are needed on every chunk: a
 //! passage a reader cannot locate in the book is a passage they cannot check.
 
+use std::collections::BTreeMap;
 use std::sync::LazyLock;
 
 use regex::Regex;
@@ -117,12 +118,22 @@ pub fn chapters(markdown: &str) -> Vec<Chapter> {
         return Vec::new();
     }
 
-    let shallowest = headings
+    // The shallowest level that divides the document, which is not always the
+    // shallowest level in it. A converted EPUB carries the book's title as a
+    // lone `#` above sixty-two `##` chapters, and taking the lone one makes
+    // the whole book a single chapter — so a level used once is a title and a
+    // level used twice is a chapter map.
+    let mut counts: BTreeMap<usize, usize> = BTreeMap::new();
+    for (level, _, _) in &headings {
+        *counts.entry(*level).or_default() += 1;
+    }
+    let dividing = counts
         .iter()
-        .map(|(level, _, _)| *level)
-        .min()
+        .find(|(_, used)| **used > 1)
+        .map(|(level, _)| *level)
+        .or_else(|| counts.keys().next().copied())
         .expect("a heading");
-    headings.retain(|(level, _, _)| *level == shallowest);
+    headings.retain(|(level, _, _)| *level == dividing);
 
     let page_at = PageIndex::new(markdown);
     let mut chapters = Vec::with_capacity(headings.len());
@@ -245,6 +256,22 @@ mod tests {
         assert_eq!(pages[0].number, Some(7));
     }
 
+    #[test]
+    fn a_lone_shallow_heading_is_a_title_rather_than_a_chapter_map() {
+        // What a converted EPUB looks like: the book's title as the only
+        // `#`, and every actual chapter a `##` under it. Taking the lone
+        // one makes the whole book a single chapter.
+        let markdown = "# The Whole Book\n\n## Chapter One\n\ntext\n\n## Chapter Two\n\ntext";
+        let found = chapters(markdown);
+        assert_eq!(
+            found
+                .iter()
+                .map(|one| one.title.as_str())
+                .collect::<Vec<_>>(),
+            ["Chapter One", "Chapter Two"]
+        );
+    }
+
     #[test]
     fn chapters_come_from_the_shallowest_heading_level_present() {
         let markdown = "## Alpha\n\ntext\n\n### Sub\n\ntext\n\n## Beta\n\ntext";
diff --git a/crates/mdscrub/src/heading.rs b/crates/mdscrub/src/heading.rs
index 2d86409..10cc0b1 100644
--- a/crates/mdscrub/src/heading.rs
+++ b/crates/mdscrub/src/heading.rs
@@ -18,8 +18,10 @@ fn pattern(source: &str) -> Regex {
 /// `[text](url)` — a heading wrapped in a link to its own anchor.
 static LINK: LazyLock<Regex> = LazyLock::new(|| pattern(r"\[([^\]]*)\]\([^)]*\)"));
 
-/// `[text]{.cls}` — pandoc's bracketed inline span.
-static BRACKETED: LazyLock<Regex> = LazyLock::new(|| pattern(r"\[([^\]]+)\]\{[^}]*\}"));
+/// `[text]{.cls}` — pandoc's bracketed inline span. The text may be empty:
+/// `[]{#chapter-3}` is how an anchor with nothing in it arrives, and a
+/// heading that keeps one is a chapter title with an element id in it.
+static BRACKETED: LazyLock<Regex> = LazyLock::new(|| pattern(r"\[([^\]]*)\]\{[^}]*\}"));
 
 /// A trailing `{.attr}` block.
 static ATTRIBUTE_TAIL: LazyLock<Regex> =
diff --git a/docs/decisions.md b/docs/decisions.md
index d8da4e1..6532633 100644
--- a/docs/decisions.md
+++ b/docs/decisions.md
@@ -93,6 +93,11 @@ library.
 The chapter a passage carries is the nearest heading above the point the
 passage *starts*, found by byte offset into the source.
 
+The heading level that divides a document is the shallowest one used more
+than once, not simply the shallowest one present: a converted EPUB carries the
+book's title as a lone `#` above sixty-two `##` chapters, and a level used
+once is a title rather than a chapter map.
+
 The offset has to be the passage's own. A document with no page markers is a
 single page beginning at zero, so asking where the *page* started puts every
 chunk in the book under whichever heading came first in the file — which also
diff --git a/examples/rust/Cargo.lock b/examples/rust/Cargo.lock
new file mode 100644
index 0000000..3a634fd
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+]
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diff --git a/examples/rust/Cargo.toml b/examples/rust/Cargo.toml
new file mode 100644
index 0000000..b6db021
--- /dev/null
+++ b/examples/rust/Cargo.toml
@@ -0,0 +1,16 @@
+# Standalone so that `cargo run` here does not need the workspace above it.
+[workspace]
+
+[package]
+name = "catena-example"
+version = "0.0.0"
+edition = "2024"
+rust-version = "1.85"
+publish = false
+
+[dependencies]
+booksniff = { path = "../../crates/booksniff" }
+chunkmd = { path = "../../crates/chunkmd" }
+citefind = { path = "../../crates/citefind" }
+corpus-core = { path = "../../crates/corpus-core" }
+mdscrub = { path = "../../crates/mdscrub" }
diff --git a/examples/rust/src/main.rs b/examples/rust/src/main.rs
new file mode 100644
index 0000000..3150570
--- /dev/null
+++ b/examples/rust/src/main.rs
@@ -0,0 +1,119 @@
+//! A converted book, read the whole way through in one process.
+//!
+//! The commands are filters and a subprocess is usually the right answer, but
+//! when the caller already holds the text there is nothing to serialise: the
+//! same libraries the commands are built from take a `&str` and hand back the
+//! records. This walks a file from "what even is it" to passages worth
+//! embedding and the references at the back, without a pipe anywhere.
+//!
+//!     cargo run -- book.md
+//!     cargo run          # reads the sample below
+
+use std::path::Path;
+
+/// A page of a converted book: a heading, two passages and a short
+/// bibliography, which is enough to show every stage doing something.
+const SAMPLE: &str = "\
+# III. The Second Estate
+
+The obligation ran both ways, and contemporaries said so plainly whenever
+they were asked.[^4] A lord who could not protect was a lord who could not
+command, and the rolls record the consequences.
+
+What the rolls do not say, and what has to be inferred, is how often the
+obligation was actually tested. <!-- a converter's leftover -->
+
+# Bibliography
+
+Bloch, Marc. *Feudal Society*. Translated by L. A. Manyon. London: Routledge
+and Kegan Paul, 1961.
+
+Duby, Georges. *The Three Orders: Feudal Society Imagined*. Chicago:
+University of Chicago Press, 1980.
+
+Reynolds, Susan. *Fiefs and Vassals: The Medieval Evidence Reinterpreted*.
+Oxford: Clarendon Press, 1994.
+";
+
+fn main() {
+    let (name, raw) = match std::env::args().nth(1) {
+        Some(path) => {
+            let bytes = std::fs::read(&path).unwrap_or_else(|why| {
+                eprintln!("catena-example: {path}: {why}");
+                std::process::exit(74);
+            });
+            (path, bytes)
+        }
+        None => ("sample.md".to_string(), SAMPLE.as_bytes().to_vec()),
+    };
+
+    // What the file actually is, whatever it is called. Worth asking first:
+    // a `.pdf` that is really a DjVu fails four stages later, in a way that
+    // looks like a bug in the converter.
+    let doc = booksniff::sniff(&raw.as_slice(), &name);
+    let stem = Path::new(&name).file_name().unwrap_or_default();
+    println!("{:?} is a {:?}, {} bytes", stem, doc.kind, doc.bytes);
+    for note in &doc.notes {
+        println!("  note: {note}");
+    }
+
+    // Converted markdown carries the converter's leftovers. Scrubbing before
+    // chunking means the passages are the book's words and not the tool's.
+    let markdown = String::from_utf8_lossy(&raw);
+    let clean = mdscrub::scrub(&markdown);
+
+    // The defaults are sized for a book: 512 tokens a chunk, which would put
+    // this whole sample in one. A page needs a page's budget.
+    let budgets = match std::env::args().nth(1) {
+        Some(_) => chunkmd::Budgets::default(),
+        None => chunkmd::Budgets {
+            target: 120,
+            overlap: 0,
+            min_tokens: 10,
+            ..chunkmd::Budgets::default()
+        },
+    };
+    let chunks = chunkmd::chunk(&clean, &budgets);
+    println!("\n{} passage(s):", chunks.len());
+    for chunk in &chunks {
+        let chapter = chunk.chapter.as_deref().unwrap_or("—");
+        let opening: String = chunk.text.chars().take(64).collect();
+        println!(
+            "  [{}] {:?} {} tokens, under {chapter:?}\n      {}…",
+            chunk.idx,
+            chunk.role,
+            chunk.tokens,
+            opening.replace('\n', " ")
+        );
+    }
+
+    // The references at the back. A passage whose role is `bibliography` is
+    // where they live; a note at the foot of a page is the other place, and
+    // `chunkmd` flags those so this does not have to guess.
+    let references: Vec<citefind::Reference> = chunks
+        .iter()
+        .filter(|chunk| chunk.role == corpus_core::Role::Bibliography)
+        .flat_map(|chunk| citefind::read(&chunk.text))
+        .filter(|found| !found.continuation)
+        .collect();
+
+    println!("\n{} reference(s):", references.len());
+    for found in &references {
+        let who = match found.authors.is_empty() {
+            true => "—".to_string(),
+            false => found.authors.join("; "),
+        };
+        println!(
+            "  {who}\n    {} ({}) — {:?}",
+            found.title.as_deref().unwrap_or("—"),
+            found
+                .year
+                .map(|year| year.to_string())
+                .unwrap_or_else(|| "no year".into()),
+            found.kind
+        );
+        if !found.unsettled.is_empty() {
+            println!("    could not read: {}", found.unsettled.join(", "));
+        }
+    }
+}