The Birthday Mystery - Cam Jansen, Bk 20 Author:David A. Adler, Susanna Natti (Illustrator) Not only does Cam Jansen have a birthday mystery to solve...she has one to celebrate! The Cam Jansen series marks its twentieth year with the twentieth book featuring Cam Jansen and her photographic memory. — When Cam's grandparents are robbed on their way to a surprise birthday party, Cam puts her memory to work to solve the mystery. The clu... more »e is in the story -- try to find it before Cam does!« less