A root-and-branch rethinking of how history has shaped the science of genetics. In 1900, almost no one had heard of Gregor Mendel. Ten years later, he was famous as the father of a new science of heredity—genetics. Even today, Mendelian ideas serve as a standard point of entry for learning about genes. The message students receive is plain: the twenty-first century owes an enlightened understanding of how biological inheritance really works to the persistence of an intellectual inheritance that traces back to Mendel’s garden. Disputed Inheritance turns that message on its head. As Gregory Radick shows, Mendelian ideas became foundational not because they match reality—little in nature behaves like Mendel’s peas—but because, in England in the early years of the twentieth century, a ferocious debate ended as it did. On one side was the Cambridge biologist William Bateson, who, in Mendel’s name, wanted biology and society reorganized around the recognition that heredity is destiny. On the other side was the Oxford biologist W. F. R. Weldon, who, admiring Mendel's discoveries in a limited way, thought Bateson's "Mendelism" represented a backward step, since it pushed growing knowledge of the modifying role of environments, internal and external, to the margins. Weldon's untimely death in 1906, before he could finish a book setting out his alternative vision, is, Radick suggests, what sealed the Mendelian victory. Bringing together extensive archival research with searching analyses of the nature of science and history, Disputed Inheritance challenges the way we think about genetics and its possibilities, past, present, and future.