Author D. J. MacHale is the creator of such shows as Are You Afraid of the Dark? and Ghostwriter. His screen work has given him a shrewd sense of pacing -- though the book is overlong, it will keep young fans of the fantasy/adventure genre breathlessly turning the pages.

Told in the form of Bobby's journal, which alternates with scenes of his friends receiving and reading the journal, the story careens along entertainingly, and parts of it are quite exciting.

The downside of the video connection is that the characters are from Central Casting, and the plot follows the stock formula: Boy discovers unsuspected powers, is thrown into dire situation against madly evil enemy before learning about them, finds wise mentor and warrior comrade, finds reserves of courage and strength he never knew he had, saves the world, etc.

It's a good formula, as formulas go, but it does give the books a certain been-there-done-that feel, exacerbated by the bizarre refusal of everyone to explain anything to Bobby, an obvious and annoying plot device.

Still, it's plenty of fun, and young fans of the genre aren't looking for surprises anyway.