Case Closed by Gosho Aoyama

This series of Japanese manga mysteries was recommended to OMS by mystery writer Michael Dahl. The detective, Jimmy Kudo, is a brilliant high school student who is transformed into a little boy. While trying to get his body back to normal, he takes on the name Conan Edagawa and tags along with his best friend and secret crush, Rachel Moore. But he can’t tell Rachel who he really is. Rachel’s father is an inept private investigator, and Conan solves cases for him while making him think he's solving them. Middle school readers who like a mystery will really like this series.