diff --git a/src/renderer/book.ts b/src/renderer/book.ts
index 6587c98..34c16fc 100644
--- a/src/renderer/book.ts
+++ b/src/renderer/book.ts
@@ -1,4 +1,5 @@
 import type { BookMeta } from "../main/project.js";
+import MarkdownIt from "markdown-it";
 import { alertMessage, confirmMessage, promptInput } from "./dialog.js";
 import { createMdEditor, editorText, setEditorText } from "./md-editor.js";
 import { Decoration, EditorView, type DecorationSet } from "@codemirror/view";
@@ -75,6 +76,12 @@ export type FolioAPI = {
 
 const $ = (id: string) => document.getElementById(id) as HTMLElement;
 
+// Renders the assembled manuscript into the print-only #printBook container,
+// which the print stylesheet substitutes for the whole app when exporting a
+// PDF. Plain HTML paginates reliably regardless of the editor's virtualized
+// viewport, so every chapter always reaches the printed book.
+const md = new MarkdownIt();
+
 interface ChapterEntry {
   id: string;
   title: string;
@@ -117,6 +124,7 @@ export function initBook(api: FolioAPI) {
   const fullBookView = $("fullBookView");
   const fullBookHost = $("fullBookHost");
   const fullBookStats = $("fullBookStats");
+  const printBook = $("printBook");
   const copyAllBtn = $("copyAllBtn") as HTMLButtonElement;
   const fullBookStatus = $("fullBookStatus");
   const exportPdfBtn = $("exportPdfBtn") as HTMLButtonElement;
@@ -530,9 +538,9 @@ export function initBook(api: FolioAPI) {
   // Each chapter is preserved as its own block (title + content) and we also
   // record where every chapter begins in the assembled text so the view can
   // mark chapter boundaries for page breaks without touching the chapter files.
-  async function assembleFullBook(): Promise<{ text: string; chapterStarts: number[] }> {
+  async function assembleFullBook(): Promise<{ text: string; chapterStarts: number[]; chapters: string[] }> {
     const res = await api.getBookMeta();
-    if (!res || typeof res !== "object" || "error" in res) return { text: "", chapterStarts: [] };
+    if (!res || typeof res !== "object" || "error" in res) return { text: "", chapterStarts: [], chapters: [] };
     const book = res as BookMeta;
     const parts: string[] = [];
     const chapterStarts: number[] = [];
@@ -560,17 +568,20 @@ export function initBook(api: FolioAPI) {
         offset += joined.length + 2;
       }
     }
-    return { text: parts.join("\n\n"), chapterStarts };
+    return { text: parts.join("\n\n"), chapterStarts, chapters: parts };
   }
 
   async function renderFullBook() {
-    const { text, chapterStarts } = await assembleFullBook();
+    const { text, chapterStarts, chapters } = await assembleFullBook();
     setEditorText(fullBookEditor, text);
     const ranges = chapterStarts.slice(1).map((from) => chapterBreakLine.range(from));
     fullBookEditor.dispatch({
       effects: setChapterBreaks.of(Decoration.set(ranges, true)),
     });
     fullBookStats.textContent = `words: ${countWords(text)} · chars: ${text.length}`;
+    printBook.innerHTML = chapters
+      .map((c) => `<section class="print-chapter">${md.render(c)}</section>`)
+      .join("");
   }
 
   async function selectFullBook() {
diff --git a/src/renderer/index.css b/src/renderer/index.css
index 816d74d..e591f50 100644
--- a/src/renderer/index.css
+++ b/src/renderer/index.css
@@ -519,79 +519,107 @@ html, body {
   padding-top: 1.5rem;
 }
 
+/* ---- PDF / print output ----
+   PDF export prints the whole window via webContents.printToPDF, so the
+   print stylesheet replaces the entire app with a plain-HTML manuscript
+   (#printBook) that the renderer keeps populated from the assembled book.
+   Printing plain HTML (instead of the CodeMirror editor, which only keeps a
+   virtualized window of lines in the DOM) guarantees the PDF always contains
+   the complete book in full, no matter how long it is or where the editor is
+   scrolled. #printBook is hidden on screen and shown only when printing. */
+#printBook {
+  display: none;
+}
+
 @media print {
-  html, body, #root {
+  html, body {
     height: auto !important;
     overflow: visible !important;
-    /* Pin the page to light-on-white so the PDF is readable even when the
-       app is in dark mode (Chromium PDF export inherits the live theme). */
     color: #000 !important;
     background: #fff !important;
   }
 
-  .sidebar, .full-book-nav, .chapter-header, .editor-placeholder {
+  /* Nothing from the app is printed — sidebar, toolbar, headers, buttons,
+     modals and the live editor are all replaced by the manuscript. */
+  #root, .modal-backdrop {
     display: none !important;
   }
 
-  .editor, .full-book-view, .editor-panes {
-    height: auto !important;
-    min-height: 0 !important;
-    overflow: visible !important;
-  }
-
-  #fullBookHost .cm-editor,
-  #fullBookHost .cm-scroller,
-  #fullBookHost .cm-content {
-    height: auto !important;
-    min-height: 0 !important;
-    max-height: none !important;
-    overflow: visible !important;
-    background: #fff !important;
-    color: #000 !important;
-  }
-
-  #fullBookHost .cm-scroller {
+  #printBook {
     display: block !important;
+    font-family: var(--font-serif);
+    font-size: 12pt;
+    line-height: 1.6;
+    color: #000;
+    background: #fff;
   }
 
-  #fullBookHost .cm-content {
-    white-space: pre-wrap !important;
-  }
-
-  /* Heading and inline styling stays dark enough to read on white. */
-  #fullBookHost .cm-h1,
-  #fullBookHost .cm-h2,
-  #fullBookHost .cm-h3,
-  #fullBookHost .cm-h4,
-  #fullBookHost .cm-h5,
-  #fullBookHost .cm-h6,
-  #fullBookHost .cm-strong,
-  #fullBookHost .cm-em,
-  #fullBookHost .cm-code {
-    color: #000 !important;
-  }
-
-  #fullBookHost .cm-link { color: #1a0dab !important; }
-  #fullBookHost .cm-url,
-  #fullBookHost .cm-quote,
-  #fullBookHost .cm-hr,
-  #fullBookHost .cm-comment {
-    color: #444 !important;
-  }
-
-  #fullBookHost .cm-code {
-    background: #f2f2f2 !important;
-  }
-
-  /* Every chapter after the first starts on a new printed page. The first
-     chapter keeps its natural position (no blank page before it). */
-  #fullBookHost .cm-line.chapter-break {
+  /* Every chapter after the first starts on a new page. The first chapter
+     keeps its natural position (no blank page before it). */
+  #printBook .print-chapter {
     break-before: page;
     page-break-before: always;
-    border-top: none;
-    margin-top: 0;
-    padding-top: 0;
   }
+  #printBook .print-chapter:first-child {
+    break-before: auto;
+    page-break-before: auto;
+  }
+
+  #printBook h1,
+  #printBook h2,
+  #printBook h3,
+  #printBook h4,
+  #printBook h5,
+  #printBook h6 {
+    margin: 0 0 0.7em;
+    line-height: 1.3;
+    color: #000;
+  }
+  #printBook h1 { font-size: 1.7em; }
+  #printBook h2 { font-size: 1.45em; }
+  #printBook h3 { font-size: 1.25em; }
+  #printBook h4 { font-size: 1.1em; }
+
+  #printBook p,
+  #printBook ul,
+  #printBook ol,
+  #printBook blockquote,
+  #printBook pre,
+  #printBook table {
+    margin: 0 0 0.8em;
+  }
+  #printBook ul, #printBook ol { padding-left: 1.5em; }
+  #printBook blockquote {
+    padding-left: 1em;
+    border-left: 3px solid #999;
+    color: #333;
+  }
+  #printBook pre {
+    background: #f2f2f2;
+    padding: 8px;
+    white-space: pre-wrap;
+    font-size: 0.9em;
+  }
+  #printBook code {
+    font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, monospace;
+    background: #f2f2f2;
+    padding: 1px 4px;
+    border-radius: 3px;
+    font-size: 0.9em;
+  }
+  #printBook pre code { padding: 0; background: none; }
+  #printBook a { color: #1a0dab; }
+  #printBook hr {
+    border: none;
+    border-top: 1px solid #000;
+    margin: 1em 0;
+  }
+  #printBook table { border-collapse: collapse; width: 100%; }
+  #printBook th, #printBook td {
+    border: 1px solid #666;
+    padding: 4px 8px;
+  }
+  #printBook img { max-width: 100%; }
 }
 
 /* ---- editor toolbar ---- */
diff --git a/src/renderer/index.html b/src/renderer/index.html
index e4eafc0..b19a630 100644
--- a/src/renderer/index.html
+++ b/src/renderer/index.html
@@ -185,6 +185,7 @@
         </div>
       </main>
     </div>
+    <div id="printBook" aria-hidden="true"></div>
     <div class="modal-backdrop hidden" id="modalBackdrop">
       <div class="modal" role="dialog" aria-modal="true">
         <h3 class="modal-title" id="modalTitle"></h3>
diff --git a/tests/selftest-scenario.js b/tests/selftest-scenario.js
index 06d3421..b6c6a2a 100644
--- a/tests/selftest-scenario.js
+++ b/tests/selftest-scenario.js
@@ -270,7 +270,7 @@ const BOOK2_DIR = __BOOKDIR2_VALUE__;
     const rawCss = await (await fetch("./index.css")).text();
     out.printBreakRule = /break-before\s*:\s*page/.test(rawCss);
     out.printBreakFallback = /page-break-before\s*:\s*always/.test(rawCss);
-    out.printBreakScoped = /#fullBookHost\s+\.cm-line\.chapter-break/.test(rawCss);
+    out.printBreakScoped = /\.print-chapter\s*{[^}]*break-before\s*:\s*page/.test(rawCss);
 
     document.getElementById("copyAllBtn").click();
     await new Promise((r) => setTimeout(r, 200));
@@ -435,6 +435,55 @@ const BOOK2_DIR = __BOOKDIR2_VALUE__;
       pdfRes.bytes > 500 &&
       pdfRes.pdfOk === true;
 
+    // The printed book comes from the plain-HTML #printBook container (the
+    // print stylesheet hides the whole app and shows #printBook instead), so
+    // the PDF can never be limited to the CodeMirror viewport. Verify the
+    // container is hidden on screen and carries every chapter.
+    const printBookEl = document.getElementById("printBook");
+    out.printBookHiddenOnScreen = getComputedStyle(printBookEl).display === "none";
+    const printChapters = () =>
+      Array.from(document.querySelectorAll("#printBook .print-chapter"));
+    const pcsAtSmallBook = printChapters();
+    out.printBookChapterCount = pcsAtSmallBook.length;
+    out.printBookHasAllChapters =
+      pcsAtSmallBook.length === 3 &&
+      pcsAtSmallBook.some((s) => s.textContent.includes("Gamma text")) &&
+      pcsAtSmallBook.some((s) => s.textContent.includes("Beta body without heading")) &&
+      pcsAtSmallBook.some((s) => s.querySelector("h1")?.textContent === "Empty");
+
+    // Long book: every line must reach the print DOM — the guard against the
+    // "PDF does not show the full book" bug where a long manuscript was cut
+    // off after the first screenful.
+    const longLines = Array.from(
+      { length: 1500 },
+      (_, i) => `Line ${i} of a very long chapter that must all reach the printed book.`
+    );
+    const veryLongId = (await window.folio.createChapter("Very Long")).id;
+    await window.folio.saveChapter(veryLongId, longLines.join("\n"));
+    await new Promise((r) => setTimeout(r, 500));
+    document.getElementById("fullBookBtn").click();
+    await new Promise((r) => setTimeout(r, 400));
+    const printBookText = printBookEl.textContent;
+    out.printBookHasFirstLongLine = printBookText.includes("Line 0 of a very long chapter");
+    out.printBookHasLastLongLine = printBookText.includes("Line 1499 of a very long chapter");
+    out.printBookLongChapterCount = printChapters().length;
+    out.printBookLongFull =
+      out.printBookHasFirstLongLine &&
+      out.printBookHasLastLongLine &&
+      printChapters().length === 4;
+
+    const pdfLongRes = await window.folio.exportPdf();
+    out.pdfLongExport =
+      pdfLongRes && "filePath" in pdfLongRes
+        ? { filePath: pdfLongRes.filePath, bytes: pdfLongRes.bytes, pdfOk: pdfLongRes.pdfOk }
+        : pdfLongRes;
+    out.pdfLongExportOk =
+      !!pdfLongRes &&
+      !("error" in pdfLongRes) &&
+      "filePath" in pdfLongRes &&
+      pdfLongRes.bytes > pdfRes.bytes * 2 &&
+      pdfLongRes.pdfOk === true;
+
     const okFlags = [
       "dndMoved",
       "kbMoved",
@@ -484,6 +533,10 @@ const BOOK2_DIR = __BOOKDIR2_VALUE__;
       "pdfExportPdfVisible",
       "pdfStatusShown",
       "pdfExportOk",
+      "printBookHiddenOnScreen",
+      "printBookHasAllChapters",
+      "printBookLongFull",
+      "pdfLongExportOk",
     ];
     out.all = okFlags.every((f) => out[f] === true);
   } catch (e) {