diff --git a/DroidFish/res/values/strings.xml b/DroidFish/res/values/strings.xml
index 375afa6..70b5ebb 100644
--- a/DroidFish/res/values/strings.xml
+++ b/DroidFish/res/values/strings.xml
@@ -72,6 +72,7 @@ you are not actively using the program.\
     <string name="select_en_passant_file">Select En Passant File</string>
     <string name="edit_move_counters">Edit Move Counters</string>
     <string name="internal_book">&lt;Internal Book&gt;</string>
+    <string name="eco_book">&lt;ECO Book&gt;</string>
     <string name="select_opening_book_file">Select opening book file</string>
     <string name="select_chess_engine">Select Chess Engine</string>
     <string name="select_pgn_file">Open PGN file</string>
diff --git a/DroidFish/src/org/petero/droidfish/DroidFish.java b/DroidFish/src/org/petero/droidfish/DroidFish.java
index c7eeddc..8007ac1 100644
--- a/DroidFish/src/org/petero/droidfish/DroidFish.java
+++ b/DroidFish/src/org/petero/droidfish/DroidFish.java
@@ -1430,7 +1430,9 @@ public class DroidFish extends Activity
 
     private final void setBookOptions() {
         BookOptions options = new BookOptions(bookOptions);
-        if (options.filename.length() > 0) {
+        if (options.filename.isEmpty())
+            options.filename = "internal:";
+        if (!options.filename.equals("internal:") && !options.filename.equals("eco:")) {
             String sep = File.separator;
             if (!options.filename.startsWith(sep)) {
                 File extDir = Environment.getExternalStorageDirectory();
@@ -2376,12 +2378,13 @@ public class DroidFish extends Activity
             }
         });
         final int numFiles = fileNames.length;
-        CharSequence[] items = new CharSequence[numFiles + 1];
+        CharSequence[] items = new CharSequence[numFiles + 2];
         for (int i = 0; i < numFiles; i++)
             items[i] = fileNames[i];
         items[numFiles] = getString(R.string.internal_book);
+        items[numFiles + 1] = getString(R.string.eco_book);
         final CharSequence[] finalItems = items;
-        int defaultItem = numFiles;
+        int defaultItem = bookOptions.filename.equals("eco:") ? numFiles + 1 : numFiles;
         for (int i = 0; i < numFiles; i++) {
             if (bookOptions.filename.equals(items[i])) {
                 defaultItem = i;
@@ -2393,8 +2396,12 @@ public class DroidFish extends Activity
         builder.setSingleChoiceItems(items, defaultItem, new DialogInterface.OnClickListener() {
             public void onClick(DialogInterface dialog, int item) {
                 Editor editor = settings.edit();
-                String bookFile = "";
-                if (item < numFiles)
+                final String bookFile;
+                if (item == numFiles)
+                    bookFile = "internal:";
+                else if (item == numFiles + 1)
+                    bookFile = "eco:";
+                else
                     bookFile = finalItems[item].toString();
                 editor.putString("bookFile", bookFile);
                 editor.commit();
diff --git a/DroidFish/src/org/petero/droidfish/book/DroidBook.java b/DroidFish/src/org/petero/droidfish/book/DroidBook.java
index 83cc9f6..ce8c025 100644
--- a/DroidFish/src/org/petero/droidfish/book/DroidBook.java
+++ b/DroidFish/src/org/petero/droidfish/book/DroidBook.java
@@ -54,6 +54,7 @@ public final class DroidBook {
     private Random rndGen = new SecureRandom();
 
     private IOpeningBook externalBook = new NullBook();
+    private IOpeningBook ecoBook = new EcoBook();
     private IOpeningBook internalBook = new InternalBook();
     private BookOptions options = null;
 
@@ -78,6 +79,7 @@ public final class DroidBook {
         else
             externalBook = new NullBook();
         externalBook.setOptions(options);
+        ecoBook.setOptions(options);
         internalBook.setOptions(options);
     }
 
@@ -86,7 +88,7 @@ public final class DroidBook {
         if ((options != null) && (pos.fullMoveCounter > options.maxLength))
             return null;
         List<BookEntry> bookMoves = getBook().getBookEntries(pos);
-        if (bookMoves == null)
+        if (bookMoves == null || bookMoves.isEmpty())
             return null;
 
         ArrayList<Move> legalMoves = new MoveGen().legalMoves(pos);
@@ -178,6 +180,8 @@ public final class DroidBook {
     private final IOpeningBook getBook() {
         if (externalBook.enabled()) {
             return externalBook;
+        } else if (ecoBook.enabled()) {
+            return ecoBook;
         } else {
             return internalBook;
         }
diff --git a/DroidFish/src/org/petero/droidfish/book/EcoBook.java b/DroidFish/src/org/petero/droidfish/book/EcoBook.java
new file mode 100644
index 0000000..37d238c
--- /dev/null
+++ b/DroidFish/src/org/petero/droidfish/book/EcoBook.java
@@ -0,0 +1,38 @@
+package org.petero.droidfish.book;
+
+import java.util.ArrayList;
+
+import org.petero.droidfish.book.DroidBook.BookEntry;
+import org.petero.droidfish.gamelogic.Move;
+import org.petero.droidfish.gamelogic.Position;
+
+/** Opening book containing all moves that define the ECO opening classifications. */
+public class EcoBook implements IOpeningBook {
+    private boolean enabled = false;
+
+    /** Constructor. */
+    EcoBook() {
+    }
+
+    @Override
+    public boolean enabled() {
+        return enabled;
+    }
+
+    @Override
+    public void setOptions(BookOptions options) {
+        enabled = options.filename.equals("eco:");
+    }
+
+    @Override
+    public ArrayList<BookEntry> getBookEntries(Position pos) {
+        ArrayList<Move> moves = EcoDb.getInstance().getMoves(pos);
+        ArrayList<BookEntry> entries = new ArrayList<BookEntry>();
+        for (int i = 0; i < moves.size(); i++) {
+            BookEntry be = new BookEntry(moves.get(i));
+            be.weight = 10000 - i;
+            entries.add(be);
+        }
+        return entries;
+    }
+}
diff --git a/DroidFish/src/org/petero/droidfish/book/EcoDb.java b/DroidFish/src/org/petero/droidfish/book/EcoDb.java
index 5a586aa..2138fbe 100644
--- a/DroidFish/src/org/petero/droidfish/book/EcoDb.java
+++ b/DroidFish/src/org/petero/droidfish/book/EcoDb.java
@@ -148,6 +148,37 @@ public class EcoDb {
         return new Pair<String, Integer>("", 0);
     }
 
+    /** Get all moves in the ECO tree from a given position. */
+    public ArrayList<Move> getMoves(Position pos) {
+        ArrayList<Move> moves = new ArrayList<Move>();
+        long hash = pos.zobristHash();
+        Short idx = posHashToNodeIdx.get(hash);
+        if (idx != null) {
+            Node node = readNode(idx);
+            int child = node.firstChild;
+            while (child != -1) {
+                node = readNode(child);
+                moves.add(Move.fromCompressed(node.move));
+                child = node.nextSibling;
+            }
+            ArrayList<Short> lst = posHashToNodeIdx2.get(hash);
+            if (lst != null) {
+                for (Short idx2 : lst) {
+                    node = readNode(idx2);
+                    child = node.firstChild;
+                    while (child != -1) {
+                        node = readNode(child);
+                        Move m = Move.fromCompressed(node.move);
+                        if (!moves.contains(m))
+                            moves.add(m);
+                        child = node.nextSibling;
+                    }
+                }
+            }
+        }
+        return moves;
+    }
+
 
     private static class Node {
         int move;       // Move (compressed) leading to the position corresponding to this node
diff --git a/DroidFish/src/org/petero/droidfish/book/InternalBook.java b/DroidFish/src/org/petero/droidfish/book/InternalBook.java
index eb63205..1098816 100644
--- a/DroidFish/src/org/petero/droidfish/book/InternalBook.java
+++ b/DroidFish/src/org/petero/droidfish/book/InternalBook.java
@@ -38,6 +38,7 @@ import android.annotation.SuppressLint;
 final class InternalBook implements IOpeningBook {
     private static HashMap<Long, ArrayList<BookEntry>> bookMap;
     private static int numBookMoves = -1;
+    private boolean enabled = false;
 
     InternalBook() {
         Thread t = new Thread(new Runnable() {
@@ -50,13 +51,9 @@ final class InternalBook implements IOpeningBook {
         t.start();
     }
 
-    static boolean canHandle(String filename) {
-        return filename.length() == 0;
-    }
-
     @Override
     public boolean enabled() {
-        return true;
+        return enabled;
     }
 
     @Override
@@ -76,6 +73,7 @@ final class InternalBook implements IOpeningBook {
 
     @Override
     public void setOptions(BookOptions options) {
+        enabled = options.filename.equals("internal:");
     }
 
     private synchronized final void initInternalBook() {