The Zookeeper's Wife

In her capaciously researched, gushingly overwritten The Zookeeper's Wife, Diane Ackerman (A Natural History of the Senses) recounts the true story of Antonina and Jan Zabinski, Warsaw zookeepers who, during World War II, transformed their zoo into a hideout for some 300 Jews fleeing the Nazis. Ackerman has trouble staying focused on her central characters, digressing so often that you sometimes lose the narrative thread. But what odd, captivating digressions these are: about the history of Europe's wild horses; the beauty institute dedicated to helping Polish Jews pass as Aryan; the history of the Pogo stick; and the smell of the kakapo parrot — ''like an old clarinet case.'' B+