Combination Locking Book Safe. The locking book safe looks like an English Dictionary on the book shelf. However it has a combination lock and has plenty of room inside for a small pistol, cash, jewelry, credit cards and much more. The interior dimensions of the safe are 9 1/2″ x 7 7/8″ x 2 5/8″. The outer dimensions are 9 5/8″ x 8 1/8″ x 3 1/8″.