This young adult fantasy novel by J.K. Rowling is, in the words of my oldest daughter, neither too silly nor too dark. When I realized my youngest daughter was rereading the series for the nth time, I thought I would reread them as well. I think this was also the last book in the series which had a dedicated editor. This is a delightful book, and the blurb on the back tells what it's about; "For twelve long years, the dread fortress of Azkaban held an infamous prisoner named Sirius Black. Convicted of killing thirteen people with a single curse, he was said to be the heir apparent to the Dark Lord, Voldemort. Now he has escaped, leaving only two clues as to where he might be headed: Harry Potter's defeat of You-Know-Who was Black's downfall as well. And the Azkaban guards heard Black muttering in his sleep, ' He's at Hogwarts... he's at Hogwarts.' Harry Potter isn't safe, not even within the walls of his magical school, surrounded by his friends. Because on top of it all, there may well be a traitor in their midst."