diff --git a/src/org/geometerplus/fbreader/book/Book.java b/src/org/geometerplus/fbreader/book/Book.java
index 8e72222a1..8e503ea67 100644
--- a/src/org/geometerplus/fbreader/book/Book.java
+++ b/src/org/geometerplus/fbreader/book/Book.java
@@ -41,11 +41,13 @@ import org.geometerplus.fbreader.library.Library;
 
 public class Book {
 	public static Book getById(long bookId) {
-		final Book book = BooksDatabase.Instance().loadBook(bookId);
+		final BooksDatabase database = BooksDatabase.Instance();
+
+		final Book book = database.loadBook(bookId);
 		if (book == null) {
 			return null;
 		}
-		book.loadLists();
+		book.loadLists(database);
 
 		final ZLFile bookFile = book.File;
 		final ZLPhysicalFile physicalFile = bookFile.getPhysicalFile();
@@ -56,7 +58,7 @@ public class Book {
 			return null;
 		}
 
-		FileInfoSet fileInfos = new FileInfoSet(BooksDatabase.Instance(), physicalFile);
+		FileInfoSet fileInfos = new FileInfoSet(database, physicalFile);
 		if (fileInfos.check(physicalFile, physicalFile != bookFile)) {
 			return book;
 		}
@@ -80,11 +82,12 @@ public class Book {
 			return null;
 		}
 
-		final FileInfoSet fileInfos = new FileInfoSet(BooksDatabase.Instance(), bookFile);
+		final BooksDatabase database = BooksDatabase.Instance();
+		final FileInfoSet fileInfos = new FileInfoSet(database, bookFile);
 
-		Book book = BooksDatabase.Instance().loadBookByFile(fileInfos.getId(bookFile), bookFile);
+		Book book = database.loadBookByFile(fileInfos.getId(bookFile), bookFile);
 		if (book != null) {
-			book.loadLists();
+			book.loadLists(database);
 		}
 
 		if (book != null && fileInfos.check(physicalFile, physicalFile != bookFile)) {
@@ -197,8 +200,7 @@ public class Book {
 		}
 	}
 
-	private void loadLists() {
-		final BooksDatabase database = BooksDatabase.Instance();
+	void loadLists(BooksDatabase database) {
 		myAuthors = database.loadAuthors(myId);
 		myTags = database.loadTags(myId);
 		mySeriesInfo = database.loadSeriesInfo(myId);
@@ -405,10 +407,14 @@ public class Book {
 	}
 
 	public boolean save() {
-		if (myIsSaved) {
+		return save(BooksDatabase.Instance(), false);
+	}
+
+	boolean save(final BooksDatabase database, boolean force) {
+		if (!force && myIsSaved) {
 			return false;
 		}
-		final BooksDatabase database = BooksDatabase.Instance();
+
 		database.executeAsATransaction(new Runnable() {
 			public void run() {
 				if (myId >= 0) {
@@ -416,7 +422,11 @@ public class Book {
 					database.updateBookInfo(myId, fileInfos.getId(File), myEncoding, myLanguage, myTitle);
 				} else {
 					myId = database.insertBookInfo(File, myEncoding, myLanguage, myTitle);
-					storeAllVisitedHyperinks();
+					if (myId != -1 && myVisitedHyperlinks != null) {
+						for (String linkId : myVisitedHyperlinks) {
+							database.addVisitedHyperlink(myId, linkId);
+						}
+					}
 				}
 
 				long index = 0;
@@ -447,34 +457,34 @@ public class Book {
 	}
 
 	private Set<String> myVisitedHyperlinks;
-	private void initHyperlinkSet() {
+	private void initHyperlinkSet(BooksDatabase database) {
 		if (myVisitedHyperlinks == null) {
 			myVisitedHyperlinks = new TreeSet<String>();
 			if (myId != -1) {
-				myVisitedHyperlinks.addAll(BooksDatabase.Instance().loadVisitedHyperlinks(myId));
+				myVisitedHyperlinks.addAll(database.loadVisitedHyperlinks(myId));
 			}
 		}
 	}
 
 	public boolean isHyperlinkVisited(String linkId) {
-		initHyperlinkSet();
+		return isHyperlinkVisited(BooksDatabase.Instance(), linkId);
+	}
+
+	boolean isHyperlinkVisited(BooksDatabase database, String linkId) {
+		initHyperlinkSet(database);
 		return myVisitedHyperlinks.contains(linkId);
 	}
 
 	public void markHyperlinkAsVisited(String linkId) {
-		initHyperlinkSet();
+		markHyperlinkAsVisited(BooksDatabase.Instance(), linkId);
+	}
+
+	void markHyperlinkAsVisited(BooksDatabase database, String linkId) {
+		initHyperlinkSet(database);
 		if (!myVisitedHyperlinks.contains(linkId)) {
 			myVisitedHyperlinks.add(linkId);
 			if (myId != -1) {
-				BooksDatabase.Instance().addVisitedHyperlink(myId, linkId);
-			}
-		}
-	}
-
-	private void storeAllVisitedHyperinks() {
-		if (myId != -1 && myVisitedHyperlinks != null) {
-			for (String linkId : myVisitedHyperlinks) {
-				BooksDatabase.Instance().addVisitedHyperlink(myId, linkId);
+				database.addVisitedHyperlink(myId, linkId);
 			}
 		}
 	}
diff --git a/src/org/geometerplus/fbreader/book/BookCollection.java b/src/org/geometerplus/fbreader/book/BookCollection.java
index 1732a4c8f..5c1675a06 100644
--- a/src/org/geometerplus/fbreader/book/BookCollection.java
+++ b/src/org/geometerplus/fbreader/book/BookCollection.java
@@ -29,6 +29,479 @@ import org.geometerplus.zlibrary.text.view.ZLTextPosition;
 import org.geometerplus.fbreader.Paths;
 import org.geometerplus.fbreader.bookmodel.BookReadingException;
 
-public abstract class BookCollection extends AbstractBookCollection {
+public class BookCollection extends AbstractBookCollection {
+	private final BooksDatabase myDatabase;
+	private final Map<ZLFile,Book> myBooksByFile =
+		Collections.synchronizedMap(new LinkedHashMap<ZLFile,Book>());
+	private final Map<Long,Book> myBooksById =
+		Collections.synchronizedMap(new HashMap<Long,Book>());
 
+	private static enum BuildStatus {
+		NotStarted,
+		Started,
+		Finished
+	};
+	private volatile BuildStatus myBuildStatus = BuildStatus.NotStarted;
+
+	public BookCollection(BooksDatabase db) {
+		myDatabase = db;
+	}
+
+	public int size() {
+		return myBooksByFile.size();
+	}
+
+	public Book getBookByFile(ZLFile bookFile) {
+		if (bookFile == null) {
+			return null;
+		}
+
+		Book book = myBooksByFile.get(bookFile);
+		if (book != null) {
+			return book;
+		}
+
+		final ZLPhysicalFile physicalFile = bookFile.getPhysicalFile();
+		if (physicalFile != null && !physicalFile.exists()) {
+			return null;
+		}
+
+		final FileInfoSet fileInfos = new FileInfoSet(myDatabase, bookFile);
+
+		book = myDatabase.loadBookByFile(fileInfos.getId(bookFile), bookFile);
+		if (book != null) {
+			book.loadLists(myDatabase);
+		}
+
+		if (book != null && fileInfos.check(physicalFile, physicalFile != bookFile)) {
+			addBook(book, false);
+			return book;
+		}
+		fileInfos.save();
+
+		try {
+			if (book == null) {
+				book = new Book(bookFile);
+			} else {
+				book.readMetaInfo();
+			}
+		} catch (BookReadingException e) {
+			return null;
+		}
+
+		saveBook(book, false);
+		addBook(book, false);
+		return book;
+	}
+
+	public Book getBookById(long id) {
+		Book book = myBooksById.get(id);
+		if (book != null) {
+			return book;
+		}
+
+		book = myDatabase.loadBook(id);
+		if (book == null) {
+			return null;
+		}
+		book.loadLists(myDatabase);
+
+		final ZLFile bookFile = book.File;
+		final ZLPhysicalFile physicalFile = bookFile.getPhysicalFile();
+		if (physicalFile == null) {
+			addBook(book, false);
+			return book;
+		}
+		if (!physicalFile.exists()) {
+			return null;
+		}
+
+		FileInfoSet fileInfos = new FileInfoSet(myDatabase, physicalFile);
+		if (fileInfos.check(physicalFile, physicalFile != bookFile)) {
+			addBook(book, false);
+			return book;
+		}
+		fileInfos.save();
+
+		try {
+			book.readMetaInfo();
+			addBook(book, false);
+			return book;
+		} catch (BookReadingException e) {
+			return null;
+		}
+	}
+
+	private void addBook(Book book, boolean force) {
+		if (book == null) {
+			return;
+		}
+
+		synchronized (myBooksByFile) {
+			Listener.BookEvent event = Listener.BookEvent.Added;
+			if (myBooksByFile.containsKey(book.File)) {
+				if (!force) {
+					return;
+				}
+				event = Listener.BookEvent.Updated;
+			}
+			myBooksByFile.put(book.File, book);
+			myBooksById.put(book.getId(), book);
+			fireBookEvent(event, book);
+		}
+	}
+
+	public boolean saveBook(Book book, boolean force) {
+		if (book == null) {
+			return false;
+		}
+
+		addBook(book, true);
+		return book.save(myDatabase, force);
+	}
+
+	public void removeBook(Book book, boolean deleteFromDisk) {
+		synchronized (myBooksByFile) {
+			myBooksByFile.remove(book.File);
+			myBooksById.remove(book.getId());
+
+			final List<Long> ids = myDatabase.loadRecentBookIds();
+			if (ids.remove(book.getId())) {
+				myDatabase.saveRecentBookIds(ids);
+			}
+			if (deleteFromDisk) {
+				book.File.getPhysicalFile().delete();
+			}
+		}
+		fireBookEvent(Listener.BookEvent.Removed, book);
+	}
+
+	public List<Book> books() {
+		synchronized (myBooksByFile) {
+			return new ArrayList<Book>(myBooksByFile.values());
+		}
+	}
+
+	public List<Book> books(String pattern) {
+		if (pattern == null || pattern.length() == 0) {
+			return Collections.emptyList();
+		}
+
+		final LinkedList<Book> filtered = new LinkedList<Book>();
+		for (Book b : books()) {
+			if (b.matches(pattern)) {
+				filtered.add(b);
+			}
+		}
+		return filtered;
+	}
+
+	public List<Book> recentBooks() {
+		return books(myDatabase.loadRecentBookIds());
+	}
+
+	public List<Book> favorites() {
+		return books(myDatabase.loadFavoriteIds());
+	}
+
+	private List<Book> books(List<Long> ids) {
+		final List<Book> bookList = new ArrayList<Book>(ids.size());
+		for (long id : ids) {
+			final Book book = getBookById(id);
+			if (book != null) {
+				bookList.add(book);
+			}
+		}
+		return bookList;
+	}
+
+	public Book getRecentBook(int index) {
+		List<Long> recentIds = myDatabase.loadRecentBookIds();
+		return recentIds.size() > index ? getBookById(recentIds.get(index)) : null;
+	}
+
+	public void addBookToRecentList(Book book) {
+		final List<Long> ids = myDatabase.loadRecentBookIds();
+		final Long bookId = book.getId();
+		ids.remove(bookId);
+		ids.add(0, bookId);
+		if (ids.size() > 12) {
+			ids.remove(12);
+		}
+		myDatabase.saveRecentBookIds(ids);
+	}
+
+	public void setBookFavorite(Book book, boolean favorite) {
+		if (favorite) {
+			myDatabase.addToFavorites(book.getId());
+		} else {
+			myDatabase.removeFromFavorites(book.getId());
+		}
+		fireBookEvent(Listener.BookEvent.Updated, book);
+	}
+
+	public synchronized void startBuild() {
+		if (myBuildStatus != BuildStatus.NotStarted) {
+			fireBuildEvent(Listener.BuildEvent.NotStarted);
+			return;
+		}
+		myBuildStatus = BuildStatus.Started;
+
+		final Thread builder = new Thread("Library.build") {
+			public void run() {
+				try {
+					fireBuildEvent(Listener.BuildEvent.Started);
+					build();
+					fireBuildEvent(Listener.BuildEvent.Succeeded);
+				} catch (Throwable t) {
+					fireBuildEvent(Listener.BuildEvent.Failed);
+				} finally {
+					fireBuildEvent(Listener.BuildEvent.Completed);
+					myBuildStatus = BuildStatus.Finished;
+				}
+			}
+		};
+		builder.setPriority(Thread.MIN_PRIORITY);
+		builder.start();
+	}
+
+	private void build() {
+		// Step 0: get database books marked as "existing"
+		final FileInfoSet fileInfos = new FileInfoSet(myDatabase);
+		final Map<Long,Book> savedBooksByFileId = myDatabase.loadBooks(fileInfos, true);
+		final Map<Long,Book> savedBooksByBookId = new HashMap<Long,Book>();
+		for (Book b : savedBooksByFileId.values()) {
+			savedBooksByBookId.put(b.getId(), b);
+		}
+
+		// Step 1: set myDoGroupTitlesByFirstLetter value
+		//if (savedBooksByFileId.size() > 10) {
+		//	final HashSet<String> letterSet = new HashSet<String>();
+		//	for (Book book : savedBooksByFileId.values()) {
+		//		final String letter = TitleTree.firstTitleLetter(book);
+		//		if (letter != null) {
+		//			letterSet.add(letter);
+		//		}
+		//	}
+		//	myDoGroupTitlesByFirstLetter = savedBooksByFileId.values().size() > letterSet.size() * 5 / 4;
+		//}
+
+		// Step 2: check if files corresponding to "existing" books really exists;
+		//         add books to library if yes (and reload book info if needed);
+		//         remove from recent/favorites list if no;
+		//         collect newly "orphaned" books
+		final Set<Book> orphanedBooks = new HashSet<Book>();
+		final Set<ZLPhysicalFile> physicalFiles = new HashSet<ZLPhysicalFile>();
+		int count = 0;
+		for (Book book : savedBooksByFileId.values()) {
+			synchronized (this) {
+				final ZLPhysicalFile file = book.File.getPhysicalFile();
+				if (file != null) {
+					physicalFiles.add(file);
+				}
+				if (file != book.File && file != null && file.getPath().endsWith(".epub")) {
+					continue;
+				}
+				if (book.File.exists()) {
+					boolean doAdd = true;
+					if (file == null) {
+						continue;
+					}
+					if (!fileInfos.check(file, true)) {
+						try {
+							book.readMetaInfo();
+							saveBook(book, false);
+						} catch (BookReadingException e) {
+							doAdd = false;
+						}
+						file.setCached(false);
+					}
+					if (doAdd) {
+						addBook(book, false);
+					}
+				} else {
+					orphanedBooks.add(book);
+				}
+			}
+		}
+		myDatabase.setExistingFlag(orphanedBooks, false);
+
+		// Step 3: collect books from physical files; add new, update already added,
+		//         unmark orphaned as existing again, collect newly added
+		final Map<Long,Book> orphanedBooksByFileId = myDatabase.loadBooks(fileInfos, false);
+		final Set<Book> newBooks = new HashSet<Book>();
+
+		final List<ZLPhysicalFile> physicalFilesList = collectPhysicalFiles();
+		for (ZLPhysicalFile file : physicalFilesList) {
+			if (physicalFiles.contains(file)) {
+				continue;
+			}
+			collectBooks(
+				file, fileInfos,
+				savedBooksByFileId, orphanedBooksByFileId,
+				newBooks,
+				!fileInfos.check(file, true)
+			);
+			file.setCached(false);
+		}
+		
+		// Step 4: add help file
+		try {
+			final ZLFile helpFile = getHelpFile();
+			Book helpBook = savedBooksByFileId.get(fileInfos.getId(helpFile));
+			if (helpBook == null) {
+				helpBook = new Book(helpFile);
+			}
+			addBook(helpBook, false);
+		} catch (BookReadingException e) {
+			// that's impossible
+			e.printStackTrace();
+		}
+
+		// Step 5: save changes into database
+		fileInfos.save();
+
+		myDatabase.executeAsATransaction(new Runnable() {
+			public void run() {
+				for (Book book : newBooks) {
+					saveBook(book, false);
+					addBook(book, false);
+				}
+			}
+		});
+		myDatabase.setExistingFlag(newBooks, true);
+	}
+
+	public List<String> bookDirectories() {
+		return Collections.singletonList(Paths.BooksDirectoryOption().getValue());
+	}
+
+	private List<ZLPhysicalFile> collectPhysicalFiles() {
+		final Queue<ZLFile> dirQueue = new LinkedList<ZLFile>();
+		final HashSet<ZLFile> dirSet = new HashSet<ZLFile>();
+		final LinkedList<ZLPhysicalFile> fileList = new LinkedList<ZLPhysicalFile>();
+
+		for (String path : bookDirectories()) {
+			dirQueue.offer(new ZLPhysicalFile(new File(path)));
+		}
+
+		while (!dirQueue.isEmpty()) {
+			for (ZLFile file : dirQueue.poll().children()) {
+				if (file.isDirectory()) {
+					if (!dirSet.contains(file)) {
+						dirQueue.add(file);
+						dirSet.add(file);
+					}
+				} else {
+					file.setCached(true);
+					fileList.add((ZLPhysicalFile)file);
+				}
+			}
+		}
+		return fileList;
+	}
+
+	private void collectBooks(
+		ZLFile file, FileInfoSet fileInfos,
+		Map<Long,Book> savedBooksByFileId, Map<Long,Book> orphanedBooksByFileId,
+		Set<Book> newBooks,
+		boolean doReadMetaInfo
+	) {
+		final long fileId = fileInfos.getId(file);
+		if (savedBooksByFileId.get(fileId) != null) {
+			return;
+		}
+
+		try {
+			final Book book = orphanedBooksByFileId.get(fileId);
+			if (book != null) {
+				if (doReadMetaInfo) {
+					book.readMetaInfo();
+				}
+				newBooks.add(book);
+				return;
+			}
+		} catch (BookReadingException e) {
+			// ignore
+		}
+
+		try {
+			final Book book = new Book(file);
+			newBooks.add(book);
+			return;
+		} catch (BookReadingException e) {
+			// ignore
+		}
+
+		if (file.isArchive()) {
+			for (ZLFile entry : fileInfos.archiveEntries(file)) {
+				collectBooks(
+					entry, fileInfos,
+					savedBooksByFileId, orphanedBooksByFileId,
+					newBooks,
+					doReadMetaInfo
+				);
+			}
+		}
+	}
+
+	public List<Bookmark> allBookmarks() {
+		return myDatabase.loadAllVisibleBookmarks();
+	}
+
+	public List<Bookmark> invisibleBookmarks(Book book) {
+		final List<Bookmark> list = myDatabase.loadBookmarks(book.getId(), false);
+		Collections.sort(list, new Bookmark.ByTimeComparator());
+		return list;
+	}
+
+	public void saveBookmark(Bookmark bookmark) {
+		if (bookmark != null) {
+			bookmark.setId(myDatabase.saveBookmark(bookmark));
+		}
+	}
+
+	public void deleteBookmark(Bookmark bookmark) {
+		if (bookmark != null && bookmark.getId() != -1) {
+			myDatabase.deleteBookmark(bookmark);
+		}
+	}
+
+	public static ZLResourceFile getHelpFile() {
+		final Locale locale = Locale.getDefault();
+
+		ZLResourceFile file = ZLResourceFile.createResourceFile(
+			"data/help/MiniHelp." + locale.getLanguage() + "_" + locale.getCountry() + ".fb2"
+		);
+		if (file.exists()) {
+			return file;
+		}
+
+		file = ZLResourceFile.createResourceFile(
+			"data/help/MiniHelp." + locale.getLanguage() + ".fb2"
+		);
+		if (file.exists()) {
+			return file;
+		}
+
+		return ZLResourceFile.createResourceFile("data/help/MiniHelp.en.fb2");
+	}
+
+	public ZLTextPosition getStoredPosition(long bookId) {
+		return myDatabase.getStoredPosition(bookId);
+	}
+
+	public void storePosition(long bookId, ZLTextPosition position) {
+		if (bookId != -1) {
+			myDatabase.storePosition(bookId, position);
+		}
+	}
+
+	public boolean isHyperlinkVisited(Book book, String linkId) {
+		return book.isHyperlinkVisited(myDatabase, linkId);
+	}
+
+	public void markHyperlinkAsVisited(Book book, String linkId) {
+		book.markHyperlinkAsVisited(myDatabase, linkId);
+	}
 }
diff --git a/src/org/geometerplus/fbreader/book/Bookmark.java b/src/org/geometerplus/fbreader/book/Bookmark.java
index 5aff6b99e..063c6b1bb 100644
--- a/src/org/geometerplus/fbreader/book/Bookmark.java
+++ b/src/org/geometerplus/fbreader/book/Bookmark.java
@@ -239,4 +239,8 @@ mainLoop:
 		}
 		return builder.toString();
 	}
+
+	void setId(long id) {
+		myId = id;
+	}
 }