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

Harry Potter is lucky to reach the age of thirteen, since he has already survived the murderous attacks of the feared Dark Lord on more than one occasion. But his hopes for a quiet term concentrating on Quidditch are dashed when a maniacal mass-murderer escapes from Azkaban, pursued by the soul-sucking Dementors who guard the prison. It's assumed that Hogwarts is the safest place for Harry to be. But is it a coincidence that he can feel eyes watching him in the dark, and should he be taking Professor Trelawney's ghoulish predictions seriously? From Goodreads

As usual Harry is treated badly by the Dursleys and ends up running away. My favourite character in this book is Sirius and my least favourite is Professor Trelawney. This is now starting to be a darker fantasy than the first two books.

This book qualifies for:
Goodreads Reading Challenge 2015
2015 Witches & Witchcraft Challenge
A Million More Pages Hogwarts: March Challenges (6/7)
A Million More Pages Hogwarts: Spring Fling
A Million More Pages Hogwarts: Professor Trelawney
A Million More Pages Hogwarts: Hugh Jackman
A Million More Pages Hogwarts: The Arrival
A Million More Pages Hogwarts: Harry Potter: The Ultimate Series Tour
A Million More Pages Hogwarts: Diagon Alley Supply List
A Million More Pages Hogwarts: the 50 States Amazing Book Hunt 
Crazy Challenge Connection Monopoly