A marginally successful attempt to demonstrate how three animals--the horse, the rat, and the beaver--influenced history. This is not so much about how the animals changed history as their role in it. The fascinating story of the rat and the black plague is the most effectively told, as the narrow scope allows for clear and succinct coverage. The horse and beaver receive sweeping overviews--each section is full of intriguing tidbits, but because of the broad scope, much information is omitted or left unexplained. Coverage is uneven; e.g., a large portion of the horse section is devoted to knights and armor. In drawing conclusions, Rahn fails to differentiate between proven theory and speculation. At other times, the premise is misleading, e.g., it was not the horse but gunpowder that changed warfare. The value of combining these three topics is dubious; each has been handled better in individual books. Illustrated with helpful maps and diagrams and pleasant black-and-white drawings; suggested further reading and an index are included.