Like the Aztecs and Incas who developed skilled crafts using them, or the 19th-century milliners who set them waving from every hat, Thor Hanson is fascinated with Feathers (Basic Books, $15.99). His enthusiasm is infectious and informative. A field biologist, Hanson takes readers through what is known of the evolution of birds from dinosaurs, and speculates on the first function of feathers—which was probably not flight. He presents the various capacities of feathers to warm and cool and keep birds dry, and explains how feathers scatter light to appear colorful. He provides expert commentary on the superb design of feathers and the many ways they have benefited humans, from quill pens (“pen” from Latin penna, for “feather”) to pillows to airplanes, noting that da Vinci and the Wright brothers were all avid birdwatchers.