J. K. Rowling just seems to get better and better with each new entry in the Harry Potter series and this volume, without a doubt, is the most compelling book yet. From the outset we learn that Sirius Black, a notorious criminal that even the Muggles know, has escaped from Azkaban prison. Worse yet, he is after Harry Potter who has just returned to Hogwarts School for a third term. Sinister Azkaban prison guards called Dementors have been placed all around the entrances to Hogwarts, ostensibly to keep Sirius Black away from the school. But to Harry the Dementors seem to pose as much as a threat as the escaped prisoner -- he faints from fright every time he sees one. So concerned is he about the effect they have on him that he seeks out the assistance of Professor Lupin, the new Defense against the Dark Arts teacher, who helps Harry face his fears. We have just as much humor, excellent characterization and intricate plotting in this novel as in the previous two but here Rowling introduces for the first time a layer of psychological depth, as Harry, now age 13, begins to come to terms with the death of his parents. As a result, the novel has a more somber and slightly more mature tone than its predecessors. Still, the rousing story will keep Potter fans turning the pages and the mind-blowing twist at the end of the book is likely to inspire repeated readings, of this volume if not the entire series. And, of course, everyone who reads it will now be anxiously awaiting Book Four. (Ages 9-14)