ROWLING, J[oanne] K[athleen].Harry Potter and the Prisoner of Azkaban. Illustrations by Mary GrandPre. [NY]: Scholastic [1999]. 8vo, xii 436pp. Purple half-cloth with green patterned boards and spine stamped in green. Red endpapers; b&w illustrated chapter headings. A fine copy in original color pictorial dust jacket. Signed by the author, J.K. Rowling, and the artist, Mary GrandPre.First US Edition. The third book in the bestselling Harry Potter series. Harry must face his greatest challenge yet when his infamous godfather, Sirius Black, escapes from Azkaban prison. Is he out to get Harry? Or is there more to the story than Harry's been told?