Harry Potter and the Prisoner of Azkaban (Harry Potter No. 3) - J K Rowling
The escape of Sirius Black - one time friend of Harry's parents, implicated in their murder and follower of 'You Know Who' from Azkaban, has serious implications for Harry for it would appear that Black is bent on revenge against Harry for thwarting 'You Know Who'.
Back at Hogwarts, Harry's movements are restricted by the presence of the Dementors - guards from Azkaban on the look out for Black - however, this doesn't stop him throwing himself into the new Quidditch season and going about his normal business - or at least attempting to. Despite warnings Harry is determined to get to the bottom of the mystery surrounding Sirius Black--how could this one-time close friend of his parents become the cause of their deaths?
And why does the presence of the Dementors have such a devastating effect on him, causing him to hear the last moments of his mother's life?
SEB - 7 Volumes