A Three Investigators Mystery. Author: M. V. Carey. Summary: Three young sleuths investigate the disappearance of a caveman’s bones from a museum and uncover skulduggery at a science foundation. My Thoughts: Like all the Three Investigator books, in both a good and bad way. The books tend to blend together, all following the same pattern; but each is individually interesting. Good for younger readers, while slightly older fans of the detective story would enjoy them too. They are always completely clean, and rather than always a who-dunnit, often experiment with a more nebulous mystery. Content Review: Sexual content: None. Language: None. Violence: Some people are put to sleep with anesthetic against their will. There is a short scuffle with a thief, who is picked up by the police and brought to jail.