diff --git a/backend/internal/backend/handlers_import.go b/backend/internal/backend/handlers_import.go
index 2c4e276..624168d 100644
--- a/backend/internal/backend/handlers_import.go
+++ b/backend/internal/backend/handlers_import.go
@@ -127,16 +127,17 @@ func (s *Server) handleAdminImport(w http.ResponseWriter, r *http.Request) {
 	})
 }
 
-// analyzeImportFile does a quick scan of the file to count chapters.
-// This is a placeholder - real implementation would parse PDF/EPUB properly.
+// analyzeImportFile parses the file to count chapters and extract preview lines.
 func analyzeImportFile(data []byte, fileType string) *importPreview {
-	// TODO: Implement actual PDF/EPUB parsing to count chapters
-	// For now, estimate based on file size
-	preview := &importPreview{
-		Chapters:   estimateChapters(data, fileType),
-		FirstLines: []string{},
+	count, firstLines, err := storage.AnalyzeFile(data, fileType)
+	if err != nil || count == 0 {
+		// Fall back to rough size estimate so the UI still shows something
+		count = estimateChapters(data, fileType)
+	}
+	return &importPreview{
+		Chapters:   count,
+		FirstLines: firstLines,
 	}
-	return preview
 }
 
 func estimateChapters(data []byte, fileType string) int {
diff --git a/backend/internal/storage/import.go b/backend/internal/storage/import.go
index cefe1b6..73244ce 100644
--- a/backend/internal/storage/import.go
+++ b/backend/internal/storage/import.go
@@ -54,7 +54,41 @@ func (i *importer) Import(ctx context.Context, objectKey, fileType string) ([]bo
 	return parseEPUB(data)
 }
 
-// ── PDF parsing ───────────────────────────────────────────────────────────────
+// AnalyzeFile parses the given PDF or EPUB data and returns the detected
+// chapter count and up to 3 preview lines (first non-empty line of each of
+// the first 3 chapters). It is used by the analyze-only endpoint so users
+// can preview chapter count before committing the import.
+func AnalyzeFile(data []byte, fileType string) (chapterCount int, firstLines []string, err error) {
+	var chapters []bookstore.Chapter
+	switch fileType {
+	case "pdf":
+		chapters, err = parsePDF(data)
+	case "epub":
+		chapters, err = parseEPUB(data)
+	default:
+		return 0, nil, fmt.Errorf("unsupported file type: %s", fileType)
+	}
+	if err != nil {
+		return 0, nil, err
+	}
+	chapterCount = len(chapters)
+	for i, ch := range chapters {
+		if i >= 3 {
+			break
+		}
+		line := strings.TrimSpace(ch.Content)
+		if nl := strings.Index(line, "\n"); nl > 0 {
+			line = line[:nl]
+		}
+		if len(line) > 120 {
+			line = line[:120] + "…"
+		}
+		firstLines = append(firstLines, line)
+	}
+	return chapterCount, firstLines, nil
+}
+
+
 
 func parsePDF(data []byte) ([]bookstore.Chapter, error) {
 	r, err := pdf.NewReader(bytes.NewReader(data), int64(len(data)))
diff --git a/docker-compose.yml b/docker-compose.yml
index 96cb47a..59f451c 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -307,6 +307,8 @@ services:
       # OpenTelemetry tracing
       OTEL_EXPORTER_OTLP_ENDPOINT: "${OTEL_EXPORTER_OTLP_ENDPOINT}"
       OTEL_SERVICE_NAME: "ui"
+      # Allow large PDF/EPUB uploads (adapter-node default is 512KB)
+      BODY_SIZE_LIMIT: "52428800"
       # OAuth2 providers
       GOOGLE_CLIENT_ID: "${GOOGLE_CLIENT_ID}"
       GOOGLE_CLIENT_SECRET: "${GOOGLE_CLIENT_SECRET}"