The Beak of the Finch: A Story of Evolution in Our Time is a Pulitzer Prize-winning non-fiction book written in 1994 by Jonathan Weiner, a journalist and popular science author. This substantially unchanged edition was published in 2014 with a new preface.

Weiner’s narrative relays the theory and history of evolutionary science through a case study of finch species in the Galápagos Islands. It follows evolutionists Peter and Rosemary Grant as they build substantially on the theory pioneered by Charles Darwin. Weiner sets the scene on the remote volcanic island of Daphne Major, where the Grants conduct their study. He provides thorough background information on Charles Darwin, whose encounter with the Galápagos finches as a young man sparked questions that led him to his theory. Alongside the Grants’ landmark study, The Beak of the Finch traces a parallel story of the course of Darwin’s thought

The Beak of the Finch is divided into three parts. Part 1 interweaves the history of the debate around evolution in the 19th century and the inception of Peter and Rosemary Grant’s study of evolution in Galápagos finches in the 1970s. Darwin’s theory provoked controversy upon its publication, leading to decades of theoretical debate with little definitive proof. Weiner’s narrative begins in 1973, when Peter and Rosemary travel to Daphne Major to observe evolution in the birds directly. They expect to spend a few years there but quickly find compelling evidence of evolution in the finches that warrants further study.

The Grants initiate a changing of the guard, with one graduate student after another keeping watch on the island through severe drought and a flooding wet season. As the birds’ bodies and beaks change in response to the forces of natural selection and sexual selection, the researchers see that the finches evolve rapidly and constantly, not gradually as Darwin surmised. The Grants’ study provides hard evidence of evolution in nature, profoundly impacting their field.

Part 2 explores recent research beyond the Grants’ work while following them as they synthesize their data in their lab at Princeton. These chapters pursue the question of how species originate, which Darwin did not consider despite the title of his great work. Together, the Grants’ data analysis and case studies of insects, fish, and other animals demonstrate that forces such as sexual divergence, competition, and hybridization may all potentially contribute to creating a new species. Much of the imagery seen in Part 1­—introduced as literal visual description—transforms into potent metaphor, evoking human dynamics in the behavior of birds and implying isolation, borders, limits, and the blurring thereof in the mention of islands. With references to art and religion, Weiner fosters a sense of divine mystery.

Part 3 expands the narrative scope with increasing attention to humans’ impact on evolution around the planet. Weiner describes the new ability to examine and manipulate DNA, human patterns of migration and settlement, and our stuttering attempts to control pest populations and disease. He broaches the subject of climate change due to human activity and ponders what humans’ ecological dominance means for the future of life on Earth.

In closing, Weiner describes the evolution of the human species, including the heightened consciousness that has allowed us to dominate the “thinking niche.” With both concern and hope, he ponders what might lie ahead for our species and for the planet. The Epilogue reflects on the lessons offered by evolutionary science. Weiner meditates on the breadth and the limits of human knowledge and the powerful reciprocal bond between the birds and their island.