Encyclopedia Brown tracks them down

"With a knack for trivia, Encyclopedia solves mysteries for the neighborhood kids through his detective agency. But his dad is also the chief of police, and every night, Encyclopedia helps him solve his most baffling crimes. Join Encyclopedia Brown as he solves ten confounding mysteries, involving a kidnapped ambassador, two suspicious boxers and missing money, and more. And with the clues given in each case, readers will have a chance to solve the mystery themselves!"--Page 4 of cover. Solutions are found in the back of the book.