The biological features of human beings are now measured, observed, and understood in ways never before thought possible, defining norms, establishing standards, and determining average values of human life. While the notion of "bio-politics" has been linked to everything from rational decision-making and the democratic organization of social life to eugenics and racism, Thomas Lemke offers the very first systematic overview of the history of the notion of bio-politics, exploring its relevance in contemporary theoretical debates and providing a much needed primer on the topic. Lemke explains that life has become an independent, objective and measurable factor as well as a collective reality that can be separated from concrete living beings and the singularity of individual experience. He shows how our understanding of the processes of life, the organizing of populations and the need to "govern" individuals and collectives lead to practices of correction, exclusion, normalization, and disciplining. In this lucidly written book, Lemke outlines the stakes and the debates surrounding bio-politics, providing a systematic overview of the history of the notion and making clear its relevance for sociological and contemporary theoretical debates.