Sherlock Holmes is the best known of altruistic investigators of crimes. He was conceived by Arthur Conan Doyle in the 1880s and set the precedent for many individualistic detectives in later writings. By the time Gardner created Perry Mason, writers had expanded the background of the detective from that of a private consultant or policeman to include characters from many careers and social levels, such as G. K. Chesterton's priest Father Brown and Dorothy L. Sayers's socialite Lord Peter Wimsey. Most of these characters work their way through complicated puzzles that form the heart of their mysteries, but Perry Mason mysteries are seldom so complicated. The Case of the Grinning Gorilla is a thriller that depends on suspenseful situations, such as when Mason is trapped in a bedroom with a huge gorilla who has been maddened by cruel experiments on its mind. Fast action carries the...