Jackson (The Wildlife Detectives, 2000, etc.) has crafted a fascinating compilation of human-interest stories, mythical, historical, and scientific information, and photographs about twins. Chapter topics include facts about twin bonding, conception and birth, identical and fraternal twins, multiple births, studies relating to the separation of twins, and stories of unusual twins. The text is enlivened by quotes from the many individuals whose stories are told. The neonatal nurse who cared for Brielle and Kyrie, born in 1995, relates how placing the girls together in one incubator saved the life of Brielle, who was dying when lying alone. Raymond Brandt describes how he knew that his twin had died five miles away, and Eva Mozes, a twin survivor of Auschwitz tells of the horrible experience there. Short chapters illustrated by color and black-and-white photographs are also subdivided by inserts on yellow backgrounds about related topics adding to, but not interrupting, the flow of the narrative. In the chapter about the special bonds that twins feel, for instance, Jackson discusses ancient ideas about twins and pictures the legendary twins Castor and Pollux. Another digression describes the annual gatherings of thousands of twins in Twinsberg, Ohio, and a third concerns the lives of Eng and Chang, the most-publicized conjoined twins. Medical procedures such as in vitro fertilization and ultrasound technology are briefly explained in text and illustration and a glossary/index adds simple definitions of the terms. This informative photo essay will amaze and mystify twins and singles alike. (Nonfiction. 10-13)