Feathers are an evolutionary marvel: aerodynamic, insulating, beguiling. They date back more than 100 million years. Yet their story has never been fully told.

In Feathers, biologist Thor Hanson details a sweeping natural history, as feathers have been used to fly, protect, attract, and adorn through time and place. Applying the research of paleontologists, ornithologists, biologists, engineers, and even art historians, Hanson asks: What are feathers? How did they evolve? What do they mean to us?

Engineers call feathers the most efficient insulating material ever discovered, and...