diff --git a/web/index.html b/web/index.html
index 2624b4a..4523f83 100644
--- a/web/index.html
+++ b/web/index.html
@@ -129,6 +129,10 @@
       <header class="deck-head library-bar">
         <h2 class="deck-label">library</h2>
         <span class="deck-count readout" id="library-summary"></span>
+        <div class="view-toggle">
+          <button type="button" class="view-btn" id="library-view-grid" aria-pressed="true">grid</button>
+          <button type="button" class="view-btn" id="library-view-list" aria-pressed="false">list</button>
+        </div>
         <button
           type="button"
           class="bucket-toggle readout"
diff --git a/web/src/main.ts b/web/src/main.ts
index bc96c2e..3cd7560 100644
--- a/web/src/main.ts
+++ b/web/src/main.ts
@@ -2380,6 +2380,25 @@ interface LibraryGroup {
   rows: HTMLUListElement;
 }
 
+/* ---- §9.6 poster grid (#151) -------------------------------------------- */
+
+type LibraryShape = "grid" | "list";
+
+const LIBRARY_SHAPE_KEY = "arr.libraryView";
+
+/**
+ * The grid is default and the choice is per-person — no server state. A
+ * corrupt or foreign value falls back to the grid rather than breaking open.
+ */
+function loadLibraryShape(): LibraryShape {
+  try {
+    const stored = window.localStorage.getItem(LIBRARY_SHAPE_KEY);
+    return stored === "list" ? "list" : "grid";
+  } catch {
+    return "grid";
+  }
+}
+
 function libraryMain(
   board: HTMLElement,
   movieDetail: MovieView,
@@ -2392,6 +2411,8 @@ function libraryMain(
   const summary = must<HTMLElement>("#library-summary");
   const toggle = must<HTMLButtonElement>("#library-toggle");
   const status = must<HTMLElement>("#library-status");
+  const gridBtn = must<HTMLButtonElement>("#library-view-grid");
+  const listBtn = must<HTMLButtonElement>("#library-view-list");
   const groups: { series: LibraryGroup; movies: LibraryGroup } = {
     series: {
       section: must<HTMLElement>("#library-series"),
@@ -2407,11 +2428,30 @@ function libraryMain(
 
   // §4.2: ONE toggle for everything the default view leaves out
   let showAll = false;
+  // §9.6 library view: the poster grid is default, per-person, localStorage
+  let shape = loadLibraryShape();
   let data: { series: LibrarySeries[]; movies: LibraryMovie[] } | null = null;
   let roots: Root[] = [];
   // guards a stale fetch from painting over a newer view
   let sequence = 0;
 
+  function setShape(next: LibraryShape) {
+    shape = next;
+    try {
+      window.localStorage.setItem(LIBRARY_SHAPE_KEY, next);
+    } catch {
+      // private mode or full storage: the choice just does not persist
+    }
+    gridBtn.setAttribute("aria-pressed", String(shape === "grid"));
+    listBtn.setAttribute("aria-pressed", String(shape === "list"));
+    render();
+  }
+
+  gridBtn.addEventListener("click", () => setShape("grid"));
+  listBtn.addEventListener("click", () => setShape("list"));
+  gridBtn.setAttribute("aria-pressed", String(shape === "grid"));
+  listBtn.setAttribute("aria-pressed", String(shape === "list"));
+
   function setStatus(text: string | null, tone?: "fault") {
     status.hidden = text === null;
     status.textContent = text ?? "";
@@ -2432,6 +2472,7 @@ function libraryMain(
   }
 
   function renderGroup<T>(group: LibraryGroup, items: T[], build: (item: T) => HTMLLIElement) {
+    group.rows.className = shape === "grid" ? "deck-rows grid-rows" : "deck-rows";
     group.rows.replaceChildren();
     group.section.hidden = items.length === 0;
     group.count.textContent = String(items.length);
@@ -2457,18 +2498,23 @@ function libraryMain(
 
     const seriesShown = showAll ? library.series : library.series.filter(seriesNeedsAttention);
     const moviesShown = showAll ? library.movies : library.movies.filter(movieNeedsAttention);
-    renderGroup(groups.series, seriesShown, (series) =>
-      seriesRow(series, roots, (id, origin) => {
-        navigate({ kind: "series", seriesId: id });
-        void seriesDetail.open(id, origin, view, { kind: "library" });
-      }),
-    );
-    renderGroup(groups.movies, moviesShown, (movie) =>
-      libraryRow(movie, roots, (target, origin) => {
-        navigate({ kind: "movie", movieId: target.id });
-        void movieDetail.open(target.id, origin, view, { kind: "library" });
-      }),
-    );
+
+    const openSeries = (id: number, origin: HTMLElement) => {
+      navigate({ kind: "series", seriesId: id });
+      void seriesDetail.open(id, origin, view, { kind: "library" });
+    };
+    const openMovie = (movie: LibraryMovie, origin: HTMLElement) => {
+      navigate({ kind: "movie", movieId: movie.id });
+      void movieDetail.open(movie.id, origin, view, { kind: "library" });
+    };
+
+    if (shape === "grid") {
+      renderGroup(groups.series, seriesShown, (series) => seriesCard(series, roots, openSeries));
+      renderGroup(groups.movies, moviesShown, (movie) => movieCard(movie, roots, openMovie));
+    } else {
+      renderGroup(groups.series, seriesShown, (series) => seriesRow(series, roots, openSeries));
+      renderGroup(groups.movies, moviesShown, (movie) => libraryRow(movie, roots, openMovie));
+    }
 
     if (total === 0) {
       setStatus("library is empty — the search box above adds titles");
@@ -2601,6 +2647,151 @@ function seriesRow(
   return item;
 }
 
+/**
+ * One §9.6 grid tile (#151): poster at w342, title and year beneath, then
+ * the chips the row view carries — a card is legible before it is pretty.
+ * A missing poster becomes a same-ratio placeholder carrying its title,
+ * so the grid never reflows and never has a hole in it.
+ */
+function libraryCard(
+  posterPath: string | null,
+  title: string,
+  year: number | null,
+  chips: HTMLSpanElement[],
+  open: (origin: HTMLElement) => void,
+): HTMLLIElement {
+  const item = document.createElement("li");
+  const card = document.createElement("button");
+  card.type = "button";
+  card.className = "card";
+
+  const art = document.createElement("span");
+  art.className = "card-art";
+  if (posterPath === null) {
+    const blank = document.createElement("span");
+    blank.className = "card-blank";
+    const blankTitle = document.createElement("span");
+    blankTitle.className = "card-blank-title";
+    blankTitle.textContent = title;
+    blank.append(blankTitle);
+    art.append(blank);
+  } else {
+    const img = document.createElement("img");
+    img.className = "card-poster";
+    img.loading = "lazy";
+    img.src = tmdbImage(posterPath, "w342") ?? "";
+    img.alt = `${title} poster`;
+    // hotlinked art can 404; fall back to the titled blank rather than a hole
+    img.addEventListener("error", () => {
+      const blankTitle = document.createElement("span");
+      blankTitle.className = "card-blank-title";
+      blankTitle.textContent = title;
+      const blank = document.createElement("span");
+      blank.className = "card-blank";
+      blank.append(blankTitle);
+      img.replaceWith(blank);
+    });
+    art.append(img);
+  }
+
+  const id = document.createElement("span");
+  id.className = "card-id";
+  const name = document.createElement("span");
+  name.className = "card-name";
+  name.textContent = title;
+  const when = document.createElement("span");
+  when.className = "card-year readout dim";
+  when.textContent = year === null ? "—" : String(year);
+  id.append(name, when);
+
+  const chipLine = document.createElement("span");
+  chipLine.className = "card-chips";
+  for (const chipEl of chips) {
+    chipLine.append(chipEl);
+  }
+
+  const body = document.createElement("span");
+  body.className = "card-body";
+  body.append(id, chipLine);
+
+  card.append(art, body);
+  card.addEventListener("click", () => {
+    open(card);
+  });
+  item.append(card);
+  return item;
+}
+
+function seriesCard(
+  series: LibrarySeries,
+  roots: Root[],
+  open: (id: number, origin: HTMLElement) => void,
+): HTMLLIElement {
+  const root = roots.find((candidate) => candidate.id === series.root_id);
+  const chips = [chip(root ? root.audience : `root ${series.root_id}`)];
+  if (series.wanted_episodes > 0) {
+    chips.push(
+      chip(`${series.available_episodes}/${series.wanted_episodes} eps`, (span) => {
+        span.setAttribute(
+          "aria-label",
+          `${series.available_episodes} of ${series.wanted_episodes} wanted episodes on disk`,
+        );
+      }),
+    );
+  }
+  if (series.blocked) {
+    chips.push(chip("blocked"));
+  }
+  chips.push(
+    chip(series.status, (span) => {
+      span.dataset.status = series.status;
+    }),
+  );
+  const rating = ratingChip(series.vote_average);
+  if (rating !== null) {
+    chips.push(rating);
+  }
+  return libraryCard(series.poster_path, series.title, series.year, chips, (origin) =>
+    open(series.id, origin),
+  );
+}
+
+function movieCard(
+  movie: LibraryMovie,
+  roots: Root[],
+  open: (movie: LibraryMovie, origin: HTMLElement) => void,
+): HTMLLIElement {
+  const root = roots.find((candidate) => candidate.id === movie.root_id);
+  const chips = [chip(root ? root.audience : `root ${movie.root_id}`)];
+  chips.push(
+    chip(movie.state, (span) => {
+      span.dataset.movieState = movie.state;
+    }),
+  );
+  // §5.7 honesty: a waived import is never presented as a clean match
+  const waiver = waiverLabel(movie.waiver);
+  if (waiver !== null) {
+    chips.push(
+      chip(waiver, (span) => {
+        span.dataset.verdict = "waived";
+      }),
+    );
+  }
+  if (!movie.wanted) {
+    chips.push(chip("not wanted"));
+  }
+  if (movie.blocked) {
+    chips.push(chip("blocked"));
+  }
+  const rating = ratingChip(movie.vote_average);
+  if (rating !== null) {
+    chips.push(rating);
+  }
+  return libraryCard(movie.poster_path, movie.title, movie.year, chips, (origin) =>
+    open(movie, origin),
+  );
+}
+
 /* ---- tv release deck (§9.3 for season packs and single episodes) ------- */
 
 interface TvDeckRequest {
diff --git a/web/src/style.css b/web/src/style.css
index a387e2b..fd954c3 100644
--- a/web/src/style.css
+++ b/web/src/style.css
@@ -1159,9 +1159,157 @@ body {
 }
 
 /* the toggle's own padding would inset its text past the chip column's
-   right rag; drop it so SATISFIED sits flush with the chips below */
+   right rag; with the shape toggle right of it, SATISFIED sits flush
+   against its neighbour instead of the deck edge */
 .library-bar .bucket-toggle {
   padding: 0;
+  margin-left: var(--space-2);
+}
+
+/* ---- library poster grid (§9.6, issue 151) ------------------------------ */
+
+/* the shape toggle: a joined pair, engaged side lit like any view control */
+.view-toggle {
+  margin-left: auto;
+  display: inline-flex;
+}
+
+.view-btn {
+  min-height: 1.75rem;
+  padding: 0 var(--space-2);
+  font-family: var(--font-readout);
+  font-size: var(--text-xs);
+  text-transform: uppercase;
+  letter-spacing: 0.08em;
+  color: var(--ink-faint);
+  background: none;
+  border: 1px solid var(--line);
+  cursor: pointer;
+  transition:
+    border-color 150ms var(--ease-out),
+    color 150ms var(--ease-out);
+}
+
+.view-btn + .view-btn {
+  border-left-width: 0;
+}
+
+.view-btn:hover {
+  color: var(--accent-bright);
+}
+
+.view-btn[aria-pressed="true"] {
+  color: var(--accent-bright);
+  border-color: var(--accent);
+}
+
+/* auto-fill keeps every tile the same width down to a phone, where three
+   narrow-but-legible columns beat two oversized ones */
+.deck-rows.grid-rows {
+  display: grid;
+  grid-template-columns: repeat(auto-fill, minmax(7rem, 1fr));
+  gap: var(--space-4);
+}
+
+.card {
+  display: flex;
+  flex-direction: column;
+  align-items: stretch;
+  width: 100%;
+  height: 100%;
+  padding: 0;
+  background: var(--panel);
+  border: 1px solid var(--line);
+  border-radius: var(--radius);
+  overflow: hidden;
+  text-align: left;
+  cursor: pointer;
+  transition:
+    border-color 150ms var(--ease-out),
+    transform 150ms var(--ease-out);
+}
+
+.card:hover {
+  border-color: var(--accent);
+}
+
+.card:active {
+  transform: translateY(1px);
+}
+
+/* the poster is framed evidence, like every other image on a panel */
+.card-art {
+  display: block;
+  aspect-ratio: 2 / 3;
+}
+
+.card-poster {
+  display: block;
+  width: 100%;
+  height: 100%;
+  object-fit: cover;
+  background: var(--panel-raised);
+}
+
+/* same ratio as a poster, carrying the title: the grid never has a hole */
+.card-blank {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  width: 100%;
+  height: 100%;
+  padding: var(--space-3);
+  background: var(--panel-raised);
+  box-shadow: inset 0 1px var(--highlight);
+}
+
+.card-blank-title {
+  font-family: var(--font-display);
+  font-size: var(--text-base);
+  font-weight: 600;
+  letter-spacing: 0.02em;
+  text-align: center;
+  color: var(--ink-faint);
+}
+
+.card-body {
+  display: flex;
+  flex-direction: column;
+  gap: var(--space-1);
+  padding: var(--space-2);
+}
+
+.card-id {
+  display: flex;
+  align-items: baseline;
+  gap: var(--space-1);
+  min-width: 0;
+}
+
+.card-name {
+  flex: 1;
+  /* two clamped lines: a long title stays readable where a single
+     ellipsised line at tile width would not be */
+  display: -webkit-box;
+  -webkit-box-orient: vertical;
+  -webkit-line-clamp: 2;
+  overflow: hidden;
+  font-family: var(--font-display);
+  font-size: var(--text-sm);
+  font-weight: 600;
+  letter-spacing: 0.02em;
+  color: var(--ink);
+}
+
+.card-year {
+  flex: none;
+  font-size: var(--text-2xs);
+}
+
+.card-chips {
+  display: flex;
+  flex-wrap: wrap;
+  gap: var(--space-1);
 }
 
 /* ---- series detail (§4.1 + §4.2, issue 129) --------------------------- */
@@ -1625,6 +1773,19 @@ body {
     gap: var(--space-3) var(--space-4);
   }
 
+  /* the library bar wraps to two lines at phone widths: identity and count
+     on the first, shape and satisfied toggles on the second, each label
+     whole instead of squeezed into a mid-word break */
+  .library-bar {
+    flex-wrap: wrap;
+    row-gap: var(--space-2);
+  }
+
+  .library-bar .bucket-toggle,
+  .view-btn {
+    white-space: nowrap;
+  }
+
   .rail-verdict {
     flex-basis: 100%;
     order: 3;