This book explores the socio-political implications of human heredity from the second half of the nineteenth century to the present postgenomic moment. It addresses three main phases in the politicization of heredity: the peak of radical eugenics (1900-1945), characterized by an aggressive ethos of supporting the transformation of human society via biological knowledge; the repositioning, after 1945, of biological thinking into a liberal-democratic, human rights framework; and the present postgenomic crisis in which the genome can no longer be understood as insulated from environmental signals. In Political Biology, Maurizio Meloni argues that thanks to the ascendancy of epigenetics we may be witnessing a return to soft heredity - the idea that these signals can cause changes in biology that are themselves transferable to succeeding generations. This book will be of great interest to scholars across science and technology studies, the philosophy and history of science, and political and social theory.