diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index 0b31b999e..a508877a2 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -63,7 +63,7 @@
 		</activity>
 		<activity android:name="org.geometerplus.android.fbreader.CancelActivity" android:theme="@android:style/Theme.Dialog" android:configChanges="orientation|keyboardHidden"/>
 		<activity android:name="org.geometerplus.android.fbreader.image.ImageViewActivity" android:process=":imageView" android:configChanges="orientation|keyboardHidden"/>
-		<activity android:name="org.geometerplus.android.fbreader.BookInfoActivity" android:configChanges="orientation|keyboardHidden" android:process=":library"/>
+		<activity android:name="org.geometerplus.android.fbreader.library.BookInfoActivity" android:configChanges="orientation|keyboardHidden" android:process=":library"/>
 		<service android:name="org.geometerplus.android.fbreader.library.InitializationService" android:process=":library" />
 		<receiver android:name="org.geometerplus.android.fbreader.library.KillerCallback" android:process=":library" />
 		<activity android:name="org.geometerplus.android.fbreader.library.LibraryActivity" android:launchMode="singleTask" android:process=":library" android:configChanges="orientation|keyboardHidden">
diff --git a/AndroidManifest.xml.pattern b/AndroidManifest.xml.pattern
index 71437118c..68594fddf 100644
--- a/AndroidManifest.xml.pattern
+++ b/AndroidManifest.xml.pattern
@@ -63,7 +63,7 @@
 		</activity>
 		<activity android:name="org.geometerplus.android.fbreader.CancelActivity" android:theme="@android:style/Theme.Dialog" android:configChanges="orientation|keyboardHidden"/>
 		<activity android:name="org.geometerplus.android.fbreader.image.ImageViewActivity" android:process=":imageView" android:configChanges="orientation|keyboardHidden"/>
-		<activity android:name="org.geometerplus.android.fbreader.BookInfoActivity" android:configChanges="orientation|keyboardHidden" android:process=":library"/>
+		<activity android:name="org.geometerplus.android.fbreader.library.BookInfoActivity" android:configChanges="orientation|keyboardHidden" android:process=":library"/>
 		<service android:name="org.geometerplus.android.fbreader.library.InitializationService" android:process=":library" />
 		<receiver android:name="org.geometerplus.android.fbreader.library.KillerCallback" android:process=":library" />
 		<activity android:name="org.geometerplus.android.fbreader.library.LibraryActivity" android:launchMode="singleTask" android:process=":library" android:configChanges="orientation|keyboardHidden">
diff --git a/src/org/geometerplus/fbreader/library/AuthorTree.java b/src/org/geometerplus/fbreader/library/AuthorTree.java
index 92ed38957..891900699 100644
--- a/src/org/geometerplus/fbreader/library/AuthorTree.java
+++ b/src/org/geometerplus/fbreader/library/AuthorTree.java
@@ -19,6 +19,8 @@
 
 package org.geometerplus.fbreader.library;
 
+import java.util.Collections;
+
 public class AuthorTree extends LibraryTree {
 	public final Author Author;
 
@@ -31,8 +33,14 @@ public class AuthorTree extends LibraryTree {
 		Author = author;
 	}
 
-	SeriesTree createSeriesSubTree(String series) {
-		return new SeriesTree(this, series);
+	SeriesTree getSeriesSubTree(String series) {
+		final SeriesTree temp = new SeriesTree(series);
+		int position = Collections.binarySearch(subTrees(), temp);
+		if (position >= 0) {
+			return (SeriesTree)subTrees().get(position);
+		} else {
+			return new SeriesTree(this, series, - position - 1);
+		}
 	}
 
 	@Override
diff --git a/src/org/geometerplus/fbreader/library/BookInSeriesTree.java b/src/org/geometerplus/fbreader/library/BookInSeriesTree.java
index 975ed48fd..ab7186425 100644
--- a/src/org/geometerplus/fbreader/library/BookInSeriesTree.java
+++ b/src/org/geometerplus/fbreader/library/BookInSeriesTree.java
@@ -22,8 +22,12 @@ package org.geometerplus.fbreader.library;
 import org.geometerplus.fbreader.tree.FBTree;
 
 public final class BookInSeriesTree extends BookTree {
-	BookInSeriesTree(LibraryTree parent, Book book) {
-		super(parent, book, false);
+	BookInSeriesTree(Book book) {
+		super(book, false);
+	}
+
+	BookInSeriesTree(LibraryTree parent, Book book, int position) {
+		super(parent, book, false, position);
 	}
 
 	@Override
diff --git a/src/org/geometerplus/fbreader/library/BookTree.java b/src/org/geometerplus/fbreader/library/BookTree.java
index 50382196b..e498d21ba 100644
--- a/src/org/geometerplus/fbreader/library/BookTree.java
+++ b/src/org/geometerplus/fbreader/library/BookTree.java
@@ -25,12 +25,23 @@ public class BookTree extends LibraryTree {
 	public final Book Book;
 	private final boolean myShowAuthors;
 
+	BookTree(Book book, boolean showAuthors) {
+		Book = book;
+		myShowAuthors = showAuthors;
+	}
+
 	BookTree(LibraryTree parent, Book book, boolean showAuthors) {
 		super(parent);
 		Book = book;
 		myShowAuthors = showAuthors;
 	}
 
+	BookTree(LibraryTree parent, Book book, boolean showAuthors, int position) {
+		super(parent, position);
+		Book = book;
+		myShowAuthors = showAuthors;
+	}
+
 	@Override
 	public String getName() {
 		return Book.getTitle();
diff --git a/src/org/geometerplus/fbreader/library/Library.java b/src/org/geometerplus/fbreader/library/Library.java
index 92cb0f138..f583bb00b 100644
--- a/src/org/geometerplus/fbreader/library/Library.java
+++ b/src/org/geometerplus/fbreader/library/Library.java
@@ -257,21 +257,15 @@ public final class Library {
 		myNullList.add(null);
 	}
 
-	private TagTree getTagTree(Tag tag, HashMap<Tag,TagTree> tagTreeMap) {
-		TagTree tagTree = tagTreeMap.get(tag);
-		if (tagTree == null) {
-			LibraryTree parent =
-				((tag != null) && (tag.Parent != null)) ?
-					getTagTree(tag.Parent, tagTreeMap) : getFirstLevelTree(ROOT_BY_TAG);
-			tagTree = parent.createTagSubTree(tag);
-			tagTreeMap.put(tag, tagTree);
+	private LibraryTree getTagTree(Tag tag) {
+		if (tag == null || tag.Parent == null) {
+			return getFirstLevelTree(ROOT_BY_TAG).getTagSubTree(tag);
+		} else {
+			return getTagTree(tag.Parent).getTagSubTree(tag);
 		}
-		return tagTree;
 	}
 
 	private void build() {
-		final HashMap<Tag,TagTree> tagTreeMap = new HashMap<Tag,TagTree>();
-		final HashMap<AuthorSeriesPair,SeriesTree> seriesTreeMap = new HashMap<AuthorSeriesPair,SeriesTree>();
 		final HashMap<Long,Book> bookById = new HashMap<Long,Book>();
 
 		collectBooks();
@@ -286,16 +280,12 @@ public final class Library {
 			for (Author a : authors) {
 				final AuthorTree authorTree = getFirstLevelTree(ROOT_BY_AUTHOR).getAuthorSubTree(a);
 				if (seriesInfo == null) {
-					authorTree.createBookSubTree(book, false);
+					authorTree.getBookSubTree(book, false);
 				} else {
 					final String series = seriesInfo.Name;
 					final AuthorSeriesPair pair = new AuthorSeriesPair(a, series);
-					SeriesTree seriesTree = seriesTreeMap.get(pair);
-					if (seriesTree == null) {
-						seriesTree = authorTree.createSeriesSubTree(series);
-						seriesTreeMap.put(pair, seriesTree);
-					}
-					seriesTree.createBookInSeriesSubTree(book);
+					final SeriesTree seriesTree = authorTree.getSeriesSubTree(series);
+					seriesTree.getBookInSeriesSubTree(book);
 				}
 			}
 
@@ -304,7 +294,7 @@ public final class Library {
 				tags = (List<Tag>)myNullList;
 			}
 			for (Tag t : tags) {
-				getTagTree(t, tagTreeMap).createBookSubTree(book, true);
+				getTagTree(t).getBookSubTree(book, true);
 			}
 		}
 
@@ -323,7 +313,6 @@ public final class Library {
 			doGroupTitlesByFirstLetter = myBooks.size() > letterSet.size() * 5 / 4;
 		}
 		if (doGroupTitlesByFirstLetter) {
-			final HashMap<Character,TitleTree> letterTrees = new HashMap<Character,TitleTree>();
 			for (Book book : myBooks) {
 				String title = book.getTitle();
 				if (title == null) {
@@ -334,16 +323,12 @@ public final class Library {
 					continue;
 				}
 				Character c = title.charAt(0);
-				TitleTree tree = letterTrees.get(c);
-				if (tree == null) {
-					tree = getFirstLevelTree(ROOT_BY_TITLE).createTitleSubTree(c.toString());
-					letterTrees.put(c, tree);
-				}
-				tree.createBookSubTree(book, true);
+				final TitleTree tree = getFirstLevelTree(ROOT_BY_TITLE).getTitleSubTree(c.toString());
+				tree.getBookSubTree(book, true);
 			}
 		} else {
 			for (Book book : myBooks) {
-				getFirstLevelTree(ROOT_BY_TITLE).createBookSubTree(book, true);
+				getFirstLevelTree(ROOT_BY_TITLE).getBookSubTree(book, true);
 			}
 		}
 
@@ -351,22 +336,17 @@ public final class Library {
 		for (long id : db.loadRecentBookIds()) {
 			Book book = bookById.get(id);
 			if (book != null) {
-				getFirstLevelTree(ROOT_RECENT).createBookSubTree(book, true);
+				new BookTree(getFirstLevelTree(ROOT_RECENT), book, true);
 			}
 		}
 
 		for (long id : db.loadFavoritesIds()) {
 			Book book = bookById.get(id);
 			if (book != null) {
-				getFirstLevelTree(ROOT_FAVORITES).createBookSubTree(book, true);
+				getFirstLevelTree(ROOT_FAVORITES).getBookSubTree(book, true);
 			}
 		}
 
-		getFirstLevelTree(ROOT_FAVORITES).sortAllChildren();
-		getFirstLevelTree(ROOT_BY_AUTHOR).sortAllChildren();
-		getFirstLevelTree(ROOT_BY_TITLE).sortAllChildren();
-		getFirstLevelTree(ROOT_BY_TAG).sortAllChildren();
-
 		db.executeAsATransaction(new Runnable() {
 			public void run() {
 				for (Book book : myBooks) {
@@ -418,12 +398,9 @@ public final class Library {
 					if (newSearchResults == null) {
 						newSearchResults = createNewSearchResults(pattern);
 					}
-					newSearchResults.createBookSubTree(book, true);
+					newSearchResults.getBookSubTree(book, true);
 				}
 			}
-			if (newSearchResults != null) {
-				newSearchResults.sortAllChildren();
-			}
 		}
 		return newSearchResults;
 	}
@@ -460,8 +437,7 @@ public final class Library {
 			return;
 		}
 		final LibraryTree rootFavorites = getFirstLevelTree(ROOT_FAVORITES);
-		rootFavorites.createBookSubTree(book, true);
-		rootFavorites.sortAllChildren();
+		rootFavorites.getBookSubTree(book, true);
 		BooksDatabase.Instance().addToFavorites(book.getId());
 	}
 
diff --git a/src/org/geometerplus/fbreader/library/LibraryTree.java b/src/org/geometerplus/fbreader/library/LibraryTree.java
index bd92d3d6b..eef11a7db 100644
--- a/src/org/geometerplus/fbreader/library/LibraryTree.java
+++ b/src/org/geometerplus/fbreader/library/LibraryTree.java
@@ -48,12 +48,24 @@ public abstract class LibraryTree extends FBTree {
 		return true;
 	}
 
-	TagTree createTagSubTree(Tag tag) {
-		return new TagTree(this, tag);
+	TagTree getTagSubTree(Tag tag) {
+		final TagTree temp = new TagTree(tag);
+		int position = Collections.binarySearch(subTrees(), temp);
+		if (position >= 0) {
+			return (TagTree)subTrees().get(position);
+		} else {
+			return new TagTree(this, tag, - position - 1);
+		}
 	}
 
-	TitleTree createTitleSubTree(String title) {
-		return new TitleTree(this, title);
+	TitleTree getTitleSubTree(String title) {
+		final TitleTree temp = new TitleTree(title);
+		int position = Collections.binarySearch(subTrees(), temp);
+		if (position >= 0) {
+			return (TitleTree)subTrees().get(position);
+		} else {
+			return new TitleTree(this, title, - position - 1);
+		}
 	}
 
 	AuthorTree getAuthorSubTree(Author author) {
@@ -66,8 +78,14 @@ public abstract class LibraryTree extends FBTree {
 		}
 	}
 
-	BookTree createBookSubTree(Book book, boolean showAuthors) {
-		return new BookTree(this, book, showAuthors);
+	BookTree getBookSubTree(Book book, boolean showAuthors) {
+		final BookTree temp = new BookTree(book, showAuthors);
+		int position = Collections.binarySearch(subTrees(), temp);
+		if (position >= 0) {
+			return (BookTree)subTrees().get(position);
+		} else {
+			return new BookTree(this, book, showAuthors, - position - 1);
+		}
 	}
 
 	public boolean removeBook(Book book) {
diff --git a/src/org/geometerplus/fbreader/library/SeriesTree.java b/src/org/geometerplus/fbreader/library/SeriesTree.java
index 2f581500f..150ac9f78 100644
--- a/src/org/geometerplus/fbreader/library/SeriesTree.java
+++ b/src/org/geometerplus/fbreader/library/SeriesTree.java
@@ -19,11 +19,17 @@
 
 package org.geometerplus.fbreader.library;
 
+import java.util.Collections;
+
 public final class SeriesTree extends LibraryTree {
 	public final String Series;
 
-	SeriesTree(LibraryTree parent, String series) {
-		super(parent);
+	SeriesTree(String series) {
+		Series = series;
+	}
+
+	SeriesTree(LibraryTree parent, String series, int position) {
+		super(parent, position);
 		Series = series;
 	}
 
@@ -37,8 +43,14 @@ public final class SeriesTree extends LibraryTree {
 		return getName();
 	}
 
-	BookTree createBookInSeriesSubTree(Book book) {
-		return new BookInSeriesTree(this, book);
+	BookTree getBookInSeriesSubTree(Book book) {
+		final BookInSeriesTree temp = new BookInSeriesTree(book);
+		int position = Collections.binarySearch(subTrees(), temp);
+		if (position >= 0) {
+			return (BookInSeriesTree)subTrees().get(position);
+		} else {
+			return new BookInSeriesTree(this, book, - position - 1);
+		}
 	}
 
 	@Override
diff --git a/src/org/geometerplus/fbreader/library/TagTree.java b/src/org/geometerplus/fbreader/library/TagTree.java
index 9d122ec7a..336b07d5f 100644
--- a/src/org/geometerplus/fbreader/library/TagTree.java
+++ b/src/org/geometerplus/fbreader/library/TagTree.java
@@ -22,8 +22,12 @@ package org.geometerplus.fbreader.library;
 public final class TagTree extends LibraryTree {
 	public final Tag Tag;
 
-	TagTree(LibraryTree parent, Tag tag) {
-		super(parent);
+	TagTree(Tag tag) {
+		Tag = tag;
+	}
+
+	TagTree(LibraryTree parent, Tag tag, int position) {
+		super(parent, position);
 		Tag = tag;
 	}
 
diff --git a/src/org/geometerplus/fbreader/library/TitleTree.java b/src/org/geometerplus/fbreader/library/TitleTree.java
index cdf7caffa..16319bb80 100644
--- a/src/org/geometerplus/fbreader/library/TitleTree.java
+++ b/src/org/geometerplus/fbreader/library/TitleTree.java
@@ -22,8 +22,12 @@ package org.geometerplus.fbreader.library;
 public final class TitleTree extends LibraryTree {
 	public final String Title;
 
-	TitleTree(LibraryTree parent, String title) {
-		super(parent);
+	TitleTree(String title) {
+		Title = title;
+	}
+
+	TitleTree(LibraryTree parent, String title, int position) {
+		super(parent, position);
 		Title = title;
 	}