Options in the book window
Right-click the book window and select Properties.
The number of different positions contained in the book. White and Black are not differentiated, nor are positions mirrored on the middle axis. Try entering the moves 1. e3 e5 2. e4 Nf6 3. Nc3 Bb4 and how this becomes a reverse Ruy Lopez.
Shows moves that have never been played in the current position but which lead to another position known to the tree.
Displays all moves that lead from positions in the tree to the current board position.
Displays bar graphs of the move statistics, and also gives the exact number of Elo rated games.