Zack, a boy with a propensity for supernatural experiences, and his friend Spencer learn from a '60s-era book how to have an out-of-body experience. But after flying over New York City and visiting various landmarks, the two find they don't know how to get back into their bodies. This entry in The Zack Files series (Great-Grandpa's in the Litter Box, 1996, not reviewed) is modest in its ambitions and in its amusements: The action is light, the mood quirky, and the black-and-white illustrations odd. Greenburg does not talk down to readers, although he pegs the humor on the lowest common denominator: Zack hangs from the Statue of Liberty's nostril and pretends to be ""an astral booger,"" an image that Davis picks up for a full-page, black-and-white illustration. For children making the transition to chapter books, this is readable fare, nothing more.