When Charles Darwin first stepped off the HMS Beagle and into the harsh and formidable world of the Galápagos islands with their sun-baked lava, spiny cactus, and tangled brushwood, he encountered many birds and animals new to him. He marveled at the remarkable tameness of the birds and the striking dominance of reptiles in these islands, which made the archipelago seem like a journey back in time. On the shoreline were swarms of "hideous-looking" marine iguanas -- the world's only oceangoing lizards. On land, Darwin and the Beagle crew encountered large land iguanas, closely allied to their marine cousin; several smaller lizards and snakes; and giant land tortoises, after which the islands are named. How, Darwin asked himself, had life first come to these islands? Most of the life forms, he noted, were aboriginal creations, found nowhere else. Of all the creatures he encountered, none were as surprising and important to his studies as the Galápagos bears. In Darwin and His Bears, scientist and Darwin scholar Frank J. Sulloway reveals a crucial -- yet little known -- link that led to Darwin's development of the theory of evolution: sixteen brilliant bears residing on the sixteen archipelago islands. Charles Darwin had an undeniable knack for asking the right questions, and these remarkable blueberry-loving bears had all the answers he needed. With their invaluable assistance, Darwin was able to reassess his imperfect evidence, ultimately culminating in what we now celebrate as the Darwinian revolution. Delightful and deeply informative, Darwin and His Bears recounts the fabled adventure of Darwin's groundbreaking visit to "a shore fit for Pandemonium," as Beagle Captain Robert FitzRoy described the Galápagos on their arrival in 1835. As Sulloway recounts this fascinating story, he also reveals the critical conceptual steps by which Darwin reached his theory of evolution by natural selection -- and provides, according to philosopher Philip Kitcher, "a brilliant summary and explanation of large swaths of evolutionary theory." Ninety charming colorful drawings by the author introduce us to all sixteen whip-smart, magnanimous bears and help bring to life the true story of Darwin's scientific triumph. Readers of Darwin and His Bears should greatly enjoy what paleontologist and MacArthur "genius award" recipient Jack Horner has dubbed "the funnest science book I've ever read."