As a kid, I loved the Encyclopedia Brown books. If you are not familiar with them, these books are divided up into several stories, each one about a crime (generally a minor crime) It falls to the boy detective, Encyclopedia Brown, to solve these cases. The reader is given clues throughout each story and invited to solve the mystery themselves. The answers to each mystery are in the back of the book, and the reader can then see if they were right or wrong. Really a fun book for young people, and in my case nurtured a love of mysteries that persists to this day.