Day 4: Favourite book of favourite series

Harry Potter and the Prisoner of Azkaban  - J.K. Rowling

I chose the third book. To me, this was the most complex, while still being fun. The last three were deadly serious. A bit too much. The third book found a balance between the two. It also had a bit of time travel, and I'm a sucker for that. Makes me wonder why I didn't discover Doctor Who until 2012.