All the twists and turns of time travel in J. K. Rowling's Harry Potter and the Prisoner of Azakaban are fun, but understanding them is also hard. For example, how does Harry get past the Dementor attack so that he can time travel latter and save himself from the Dementor attack? Isn't that impossible?    In this book written for the general Harry Potter fan, Richard Jones explains how this might in fact be possible and examines more generally how time travel works in the book, along with its problems. For example, did Harry and Hermione change history? Did Harry and Hermione have free will for what they did or were their actions fixed in advance? If we can time-travel to save Sirius and Buckbeak, why can't we time-travel to save others? What did Professor Dumbledore know and when did he know it? Did Hermione get younger by all her time-traveling during the school year?    Jones answers these and many other questions. He also extensively discusses fans' competing theories of how time travel works in the Prisoner of Azakaban. Also included is a brief introduction to the theories of time and time travel in physics and philosophy that are utilized in science fiction and other time travel stories, along with a bibliography of relevant works. Do physicists and philosophers think time is real? Is time-travel possible at all? Can we in fact change the past?   The second edition revises the entire text and adds new points, including comments on what Rowling said on Pottermore.com concerning time-turning.   After finishing this book, you will have a much greater understanding of both J. K. Rowling's work and a better appreciation of the problems of time and time-travel in general.