Suppose there were other spatial dimensions, beyond the three that we know--how would we see them? What would they be like? Here, Sleator paints an eerie, fascinating picture. Trading on the affections of her uncanny neighbor Omar, Laura persuades him to take her to the Fourth Dimension, a dangerous, surreal territory. Later, she in turn takes a young man there, whom she's trying to impress; they are captured by eight-limbed, three-eyed creatures--who toy with them the way thoughtless children toy with bugs--then rescued by Omar and a network of interdimensional guardians. Inconsistencies (knots either stay tied or don't, depending on where you are in the book), sloppy thinking (Laura makes 4-D food eatable by slicing it thinly), poor verbal descriptions and gratuitous sexism (guess the sex of the weird, powerful Fifth-Dimensional character who asks, "AMMMMMMM IIIIII PPPPPPRETTTTY?") mar an otherwise exciting adventure. Similar in some respects, but much inferior to A Wrinkle in Time.