From the bestselling author of A Sense of the World comes this dramatic, globe-spanning and meticulously-researched story of two scientific rivals and their race to survey all life on Earth.

In the 18th century, two men dedicated their lives to the same daunting task: identifying and describing all life on Earth. Their approaches could not have been more different. Carl Linnaeus, a pious Swedish doctor with a huckster's flair, believed that life belonged in tidy, static categories. Georges-Louis de Buffon, an aristocratic polymath and keeper of France's royal garden, viewed life as a dynamic swirl of complexities. Both began believing their work to be difficult, but not impossible—how could the planet possibly hold more than a few thousand species? Stunned by life's diversity, both fell far short of their goal. But in the process they articulated starkly divergent views on nature, on humanity's role in shaping the fate of our planet and on humanity itself.

The rivalry between these two unique, driven individuals created reverberations that still echo today. Linnaeus, with the help of acolyte explorers he called "apostles" (only half of whom returned alive), gave the world such concepts as mammal, primate and homo sapiens—but he also denied species change and promulgated racist pseudo-science. Buffon coined the term reproduction, formulated early prototypes of evolution and genetics, and argued passionately against prejudice. It was a clash that, during their lifetimes, Buffon seemed to be winning. But their posthumous fates would take a very different turn.

With elegant, propulsive prose grounded in more than a decade of research, featuring appearances by Voltaire, Benjamin Franklin and Charles Darwin, bestselling author Jason Roberts tells an unforgettable true-life tale of intertwined lives and enduring legacies, tracing an arc of insight and discovery that extends across three centuries into the present day.