*J.K. Rowling. Scholastic/Levine, $17.95 (320p) ISBN 0-439-04486-4

Fans who have been anxiously awaiting the return of young British wizard Harry Potter (and whose clamor caused the Stateside publication date to be moved up three months) will be amazed afresh. And newcomers will likely join Harry's delighted legion of followers, for this tale is perhaps even more inventive than its predecessor, Harry Potter and the Sorceror's Stone. Picking up shortly after his first year at Hogwarts School of Witchcraft and Wizardry, orphan Harry is spending the summer with his detestable Muggle (non-witch) aunt's family. Rowling briskly sets the action rolling with a mysterious warning from an elf named Dobby. The pace accelerates as Harry, now 12, is rescued from his bedroom imprisonment by his best friend Ron Weasley and his irrepressible older twin brothers in a flying car. Their school year gets off to a bad start when Harry and Ron crash-land the car at Hogwarts. More trouble soon follows, first from Harry's old nemesis, supercilious Draco Malfoy, then from a mysterious something that is petrifying Muggle-born students, culminating with Harry and Ron's friend Hermione. And once more, it's up to Harry to save the day. Rowling might be a Hogwarts graduate herself, for her ability to create such an engaging, imaginative, funny and, above all, heart-poundingly suspenseful yarn is nothing short of magical. All ages. (June)