Stan and Jan Berenstain invite readers to help solve a mystery in this beloved Beginner Book. When a dinosaur bone goes missing from the Bear Museum, it's up to the Berenstain Bears to help crack the case. From the Mummy Room to the Hall of Famous Bears, the detectives seek every possible hiding place. Can Brother and Sister Bear find the culprit in time for the museum's grand opening? Originally created by Dr. Seuss, Beginner Books encourage children to read all by themselves, with simple words and illustrations that give clues to their meaning.