The third book in the bestselling Harry Potter series, now illustrated in glorious full color by award-winning artist Jim Kay!

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.

J.K. Rowling is the author of the bestselling Harry Potter series of seven books, published between 1997 and 2007, which have sold over 450 million copies worldwide, are distributed in more than 200 territories and translated into 79 languages, and have been turned into eight blockbuster films by Warner Bros. She has written three companion volumes to the series in aid of charity: Quidditch Through the Ages and Fantastic Beasts and Where to Find Them in aid of Comic Relief; and The Tales of Beedle the Bard in aid of her children's charity Lumos. Her website and e-publisher Pottermore is the digital hub of the Wizarding World. She has recently collaborated with writer Jack Thorne and director John Tiffany on the stage play Harry Potter and the Cursed Child Parts Parts One and Two, which is now running at The Palace Theatre in London's West End. J.K. Rowling is also the author of a novel for adult readers, The Casual Vacancy, and, under the pseudonym Robert Galbraith, is the author of three crime novels featuring private detective Cormoran Strike, which are to be adapted for BBC television. Fantastic Beasts and Where to Find Them marks J.K. Rowling's screenwriting debut.

Jim Kay won the Kate Greenaway Medal in 2012 for his illustrations in A Monster Calls by Patrick Ness. Jim studied illustration at the University of Westminster and since graduating has worked in the archives of Tate Britain and the Royal Botanic Gardens at Kew. Jim has produced concept work for television and contributed to a group exhibition at the Victoria and Albert Museum in London. He now lives and works in Northamptonshire, England, with his partner and a rescued greyhound.