diff --git a/CHANGELOG.md b/CHANGELOG.md
index fa3f293..ed527b0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,47 @@ All notable changes to this project are documented here. The format follows
 [Keep a Changelog](https://keepachangelog.com/en/1.1.0/), and the project follows
 [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Fixed
+
+- **A deck read back into Markdown carries no title it never had.** PHPPresentation gives
+  every deck the title `Untitled Presentation`, and the frontmatter carried it as though
+  somebody had written it: a deck without a title came back with one, and drawing that
+  Markdown again put a title placeholder and the words "Untitled Presentation" on a slide
+  that never had a title.
+
+  The title in the frontmatter is the deck's own where the deck has one, and the first
+  slide's title where it has not — the frontmatter is the first slide's, and a `title:` in
+  it is that slide's title. So a deck whose title is on its slide and nowhere else keeps
+  it, and a deck with no title at all comes back with no `title:` line.
+
+  It is the first slide's title and not a later one's, the way it is in the other
+  direction: a `title:` in the first slide's frontmatter is that slide's title and wins
+  over its own heading. So a deck whose second slide has a title and whose first does not
+  gains no title.
+
+- **A deck read back into Markdown carries no author it never had.** PHPPresentation gives
+  every deck the author `Unknown Creator`, and that is the library's own default rather
+  than a name somebody wrote: the frontmatter carried it as though somebody had, and the
+  deck drawn from that Markdown was made by "Unknown Creator".
+
+  The author in the frontmatter is the deck's own, and a deck that carries the default
+  carries no author, so none is written.
+
+- **The slides example says what it needs when the library is not beside it.** The
+  `mdword` skill bundle carries this half's gallery as `examples/slides/` and ships no
+  `vendor/`, so `php examples/slides/build.php` died with a PHP fatal error that said
+  nothing about what was missing.
+
+  It says what the build needs and stops:
+
+  > This build needs the library itself: put a `vendor/autoload.php` in this directory's
+  > parent, or run `composer install` in the checkout it came from.
+
+  The Word half's build has said this for a while, and the two halves ship side by side in
+  one bundle, so they fail the same way.
+
 ## [0.4.0] - 2026-11-04
 
 ### Added
diff --git a/README.md b/README.md
index 43ef442..068ddad 100644
--- a/README.md
+++ b/README.md
@@ -2330,7 +2330,7 @@ echo (new PowerPointToMarkdown($path, new Options(mediaDirectory: null)))->conve
 
 ```text
 ---
-title: "Untitled Presentation"
+title: "One"
 author: "markdown-office"
 ---
 
@@ -2340,8 +2340,13 @@ Text.
 ```
 
 The frontmatter carries what the deck said about itself — its title, its author and its
-description — because a deck's own properties are the only thing about it that is not on a
-slide.
+description. The title is the deck's own where it has one, and the first slide's where it
+has not: PHPPresentation gives every deck the title `Untitled Presentation`, and that is
+its own default rather than a title somebody wrote. The frontmatter is the first slide's,
+and a `title:` in it is that slide's title — so a deck whose title is on its slide and
+nowhere else keeps it. The author is the deck's own, and the name PHPPresentation gives a
+deck that carries none — `Unknown Creator` — is a name nobody wrote, so a deck carrying it
+carries no author.
 
 What comes back is the text and the structure. What does not is the design: the type sizes,
 the colours and the geometry live in the theme and the master, and neither travels to a new
diff --git a/examples/build.php b/examples/build.php
index 8b92085..8318f47 100644
--- a/examples/build.php
+++ b/examples/build.php
@@ -11,7 +11,22 @@
  * examples/out, and a PNG of every slide beside them in examples/out/<deck>/.
  */
 
-require_once __DIR__ . '/../vendor/autoload.php';
+$autoload = __DIR__ . '/../vendor/autoload.php';
+
+// The build drives the library's own API, so it needs the library. The `mdword` skill
+// carries a copy of this directory as `examples/slides/`, with the sources and the
+// templates but not the library, where a missing `require` would say nothing.
+if (!is_file($autoload)) {
+    fwrite(
+        STDERR,
+        "This build needs the library itself: put a `vendor/autoload.php` in this directory's parent,"
+        . " or run `composer install` in the checkout it came from.\n",
+    );
+
+    exit(1);
+}
+
+require_once $autoload;
 require_once __DIR__ . '/decks.php';
 
 use MarkdownPresentation\Document\DeckParser;
diff --git a/src/Reverse/DeckWriter.php b/src/Reverse/DeckWriter.php
index 1912f86..b736323 100644
--- a/src/Reverse/DeckWriter.php
+++ b/src/Reverse/DeckWriter.php
@@ -28,6 +28,18 @@ final class DeckWriter
      */
     private const INDENT = '    ';
 
+    /**
+     * The title PHPPresentation gives a deck that carries none: its own default
+     * rather than a title somebody wrote.
+     */
+    private const DEFAULT_TITLE = 'Untitled Presentation';
+
+    /**
+     * The author PHPPresentation gives a deck that carries none: its own default
+     * rather than a name somebody wrote.
+     */
+    private const DEFAULT_AUTHOR = 'Unknown Creator';
+
     public function __construct(private readonly Options $options)
     {
     }
@@ -49,7 +61,7 @@ public function write(array $slides, DocumentProperties $properties, ?string $th
             if ($index === 0) {
                 // The deck's own frontmatter is the first slide's, so the first slide's own
                 // settings are written into it rather than beside it.
-                $frontmatter = $this->frontmatter($properties, $theme, $slide->frontmatter);
+                $frontmatter = $this->frontmatter($properties, $theme, $slide->frontmatter, $slide->title);
 
                 if ($frontmatter !== '') {
                     $body = $frontmatter . "\n" . $body;
@@ -105,20 +117,26 @@ private function settings(array $settings): string
      * the theme it was drawn in rather than in the library's own, and the design of a deck is
      * most of what a deck is.
      *
+     * The title is the deck's own where it has one and the first slide's where it has
+     * not, which is what {@see self::title()} decides.
+     *
      * @param string|null $theme The name of the theme the deck was drawn in, when it is one
      *                           a deck can name again.
      * @param array<string, string|int|bool> $own The first slide's own settings, which are
      *                           written into the deck's own block with them.
+     * @param string|null $slideTitle The title of the first slide, which stands in for the
+     *                           deck's own title where the properties carry none.
      */
     private function frontmatter(
         DocumentProperties $properties,
         ?string $theme = null,
         array $own = [],
+        ?string $slideTitle = null,
     ): string {
         $values = [
-            'title' => $properties->getTitle(),
+            'title' => $this->title($properties, $slideTitle),
             'theme' => $theme,
-            'author' => $properties->getCreator(),
+            'author' => $this->author($properties),
             'description' => $properties->getDescription(),
             ...$own,
         ];
@@ -150,6 +168,34 @@ private function frontmatter(
         return "---\n" . implode("\n", $lines) . "\n---\n";
     }
 
+    /**
+     * The title the deck's frontmatter carries, or null where it carries none.
+     *
+     * The properties' title is the deck's own, unless it is {@see self::DEFAULT_TITLE},
+     * which says nothing about a deck that carries it. The first slide's title stands in
+     * for it then: the frontmatter is the first slide's, and a `title:` in it is that
+     * slide's title, so a deck whose title is on its slide and nowhere else would lose it.
+     */
+    private function title(DocumentProperties $properties, ?string $slideTitle): ?string
+    {
+        $title = $properties->getTitle();
+
+        return $title === self::DEFAULT_TITLE ? $slideTitle : $title;
+    }
+
+    /**
+     * The author the deck's frontmatter carries, or null where it carries none.
+     *
+     * The properties' author is the deck's own, unless it is {@see self::DEFAULT_AUTHOR}:
+     * a name nobody wrote, which the Markdown would carry as though somebody had.
+     */
+    private function author(DocumentProperties $properties): ?string
+    {
+        $author = $properties->getCreator();
+
+        return $author === self::DEFAULT_AUTHOR ? null : $author;
+    }
+
     /**
      * A YAML scalar, quoted so that a colon or a hash in the value is not read
      * as syntax.
diff --git a/tests/Readme/examples-build.php b/tests/Readme/examples-build.php
new file mode 100644
index 0000000..21a782e
--- /dev/null
+++ b/tests/Readme/examples-build.php
@@ -0,0 +1,75 @@
+<?php
+
+declare(strict_types=1);
+
+use MarkdownPresentation\Tests\Support\Doctest;
+use MarkdownPresentation\Tests\Support\Scratch;
+
+/*
+ * The slides example, run the way the skill bundle runs it.
+ *
+ * The bundle carries this half's gallery as `examples/slides/` and ships no `vendor/`, so
+ * the build has to say what it needs rather than die with a fatal error that says nothing.
+ * The copy is made into a tree of its own rather than run where it lies, because the
+ * library *is* beside it here: a build that found this repository's `vendor/` would carry
+ * on and build the decks, and the test would be about nothing.
+ */
+
+/**
+ * The build of the slides example, run in a tree that holds no library.
+ *
+ * @return array{0: int, 1: string, 2: string, 3: string} The exit code, what it said on the
+ *         standard output, what it said on the error output, and the tree it ran in.
+ */
+function slidesBuildWithoutLibrary(): array
+{
+    $directory = Scratch::directoryPath('bundle');
+
+    mkdir($directory . '/examples', 0o777, true);
+
+    foreach (['build.php', 'decks.php'] as $file) {
+        copy(Doctest::root() . '/examples/' . $file, $directory . '/examples/' . $file);
+    }
+
+    $process = proc_open(
+        [PHP_BINARY, $directory . '/examples/build.php'],
+        [1 => ['pipe', 'w'], 2 => ['pipe', 'w']],
+        $pipes,
+    );
+
+    if (!is_resource($process)) {
+        throw new RuntimeException('The build could not be started.');
+    }
+
+    $out = (string) stream_get_contents($pipes[1]);
+    $errors = (string) stream_get_contents($pipes[2]);
+
+    fclose($pipes[1]);
+    fclose($pipes[2]);
+
+    return [proc_close($process), $out, $errors, $directory];
+}
+
+it('says what the slides example needs when the library is not beside it', function () {
+    [$status, $out, $errors] = slidesBuildWithoutLibrary();
+
+    expect($status)->toBe(1)
+        ->and($errors)->toContain(
+            'This build needs the library itself: put a `vendor/autoload.php` in this directory\'s parent,'
+            . ' or run `composer install` in the checkout it came from.',
+        )
+        // On the error output and not on the standard one, and not as a PHP failure: the
+        // build is there to replace a warning about a missing file.
+        ->and($out)->not->toContain('This build needs the library itself')
+        ->and($errors)->not->toContain('Warning')
+        ->and($errors)->not->toContain('Fatal error');
+});
+
+it('stops the slides example before it builds anything', function () {
+    [$status, , , $directory] = slidesBuildWithoutLibrary();
+
+    // The build says what it needs and stops there: nothing is written.
+    expect($status)->toBe(1)
+        ->and(is_dir($directory . '/examples/out'))->toBeFalse()
+        ->and(glob($directory . '/examples/*.pptx') ?: [])->toBe([]);
+});
diff --git a/tests/Unit/dead-code.php b/tests/Unit/dead-code.php
index 5ba6eb5..ddc8b39 100644
--- a/tests/Unit/dead-code.php
+++ b/tests/Unit/dead-code.php
@@ -608,6 +608,10 @@ function pagesWithClaim(string $claim): array
     // `styles.yml` is about. The phrase is the old claim, and the README has to be able to
     // say what the halves part at without saying it.
     'a theme directory serves one half' => 'a theme directory serves one half',
+
+    // The frontmatter was said to carry what is not on a slide, but a deck's title can be
+    // on its first slide and nowhere else, and the frontmatter is the first slide's.
+    'the frontmatter carries only what is not on a slide' => 'the only thing about it that is not on a slide',
 ]);
 
 it('has no decorative dividers in it', function () {
diff --git a/tests/Unit/reverse.php b/tests/Unit/reverse.php
index db4ef44..0f74482 100644
--- a/tests/Unit/reverse.php
+++ b/tests/Unit/reverse.php
@@ -891,6 +891,66 @@ static function (DocumentProperties $properties): void {
         ->and(converted($path))->toContain('author: "Fabian"');
 });
 
+it('writes no title into the frontmatter of a deck that has none', function () {
+    // PHPPresentation's own default, not a title somebody wrote: a deck carrying it says
+    // nothing about its title.
+    $path = writtenDeck("Text only.\n");
+
+    expect(converted($path))->not->toContain('title:');
+});
+
+it('writes the title of the first slide into the frontmatter of a deck that has none', function () {
+    // The frontmatter is the first slide's, and a `title:` in it is that slide's title.
+    $path = writtenDeck("# One\n\nText.\n");
+
+    expect(converted($path))->toContain('title: "One"');
+});
+
+it('takes the title of the first slide and not the title of a later one', function () {
+    // Only the first slide's title stands in: a deck whose second slide has a title and
+    // whose first does not gains none.
+    $path = writtenDeck("Text only.\n\n---\n\n# Two\n");
+
+    expect(converted($path))->not->toContain('title:');
+});
+
+it('writes the title of the deck into the frontmatter where it has one', function () {
+    // The deck's own title is the deck's, and it wins over the first slide's.
+    $path = deckWithShapes(
+        static function (AbstractSlide $slide): void {
+            placeholderShape($slide, 'title', 'What broke');
+        },
+        static function (DocumentProperties $properties): void {
+            $properties->setTitle('Harbour lights');
+        },
+    );
+
+    expect(converted($path))->toContain('title: "Harbour lights"');
+});
+
+it('writes no author into the frontmatter of a deck that has none', function () {
+    // PHPPresentation's own default, not a name somebody wrote: the Markdown carried it
+    // as though somebody had.
+    $path = deckWithShapes(
+        static function (AbstractSlide $slide): void {
+            placeholderShape($slide, 'title', 'What broke');
+        },
+    );
+
+    expect(converted($path))->not->toContain('author:');
+});
+
+it('draws the same slide again when the Markdown it came from is drawn again', function () {
+    // The round trip has to be a round trip: the Markdown a deck is read back into, drawn
+    // again, has to be the deck it came from.
+    $first = writtenDeck("# One\n\nText.\n");
+    $back = converted($first);
+    $second = writtenDeck($back);
+
+    expect(slideTexts($second))->toBe(slideTexts($first))
+        ->and(converted($second))->toBe($back);
+});
+
 it('refuses a package with more parts than the limit allows', function () {
     $path = writtenDeck("# One\n");
 
@@ -1523,15 +1583,20 @@ static function (DocumentProperties $properties): void {
 
 it('writes nothing for a block that holds nothing', function () {
     $writer = new DeckWriter(new Options(mediaDirectory: null));
+    $properties = new DocumentProperties();
+    $properties->setTitle('A deck');
 
-    expect($writer->write([
+    $markdown = $writer->write([
         new Slide(0, null, [
             Block::paragraph([]),
             Block::list([Block::item([Block::paragraph([])])]),
             Block::table([]),
             Block::image(new Image('A dot', '', '')),
         ]),
-    ], new DocumentProperties()))->toContain('---');
+    ], $properties);
+
+    // The deck's own frontmatter and nothing after it.
+    expect(trim(str_replace('---', '', $markdown)))->toBe('title: "A deck"');
 });
 
 it('leaves a picture with nothing in it out', function () {