Charise Mericle Harper, . . Houghton, $15 (32pp) ISBN 978-0-618-15626-9

Finnigan, "a squirrel of exceptional character," sits in his walnut tree and spies on an apartment building called Normal Towers. Finnigan gets the scoop on everyone, from the guy in 2A who "performs sock puppet shows for his cat" to the fellow in 5B who "wears a dish towel as a cape." The unsuspecting parties appear silhouetted in their windows, happily performing their harmless stunts. To Finnigan, Normal Towers teems with "suspicious activity," and he sends a confidential report to the president of the U.S. While he awaits word from Washington, Finnigan trains to be a "Secret Service squirrel" with the narrator, a boy who lives in 3A and dryly indulges his nutty friend. Unlike Harriet the Spy or the folks in Rear Window, Finnigan never questions his invasions of privacy, and it pays off; the president thinks "the people of Normal are perfectly normal," but nevertheless awards the snoopy squirrel a tree on the White House lawn. Harper (There Was a Bold Lady Who Wanted a Star), who illustrates in hilarious mixed-media collages and writes in a wry deadpan, plays on secret agents' mystique; Finnigan wears dark glasses and knows where to find every acorn he has ever buried. Though some readers may suspect he's not so much a squirrel as a rat, his assets are that he has firm goals and "always tells the truth." Plus, the narrator will win over nearly everyone. Ages 4-8. (Mar.)