Ten brief cases in which the reader pits his wits against those of Encyclopedia Brown, an ingenious twelve-year-old detective.

The solutions to ten mysteries solved by Leroy "Encyclopedia" Brown are given in a separate section challenging the reader to match wits with the ten-year-old mastermind of Idaville's war on crime.

Encyclopedia Brown solves ten mysteries, from recovering a client's prized tooth collection, to following a trail of paint to find a sneaky thief, and more.