Sly the Sleuth and the Code Mysteries — Donna Jo Napoli

What do a six-year-old boy speaking nonsense, a secret note, and symbols on a bathroom door all have in common? They are all codes that Sly (aka Sylvia) has to crack in order to solve a bigger mystery. Her detective agency, Sleuth for Hire, is put to the test to solve these cases for her school and neighborhood friends. Good thing Sly has some help from her cat, Taxi.

Perfect for fans of Judy Moody and Encyclopedia Brown, this is a well-written, funny, and clever new mystery in the series. According to The Bulletin, Sly is ?as likable a protagonist as Cam Jansen, [and she] merits her own cadre of loyal fans.?