"Pickering's is the most complete work on Comte's life and thought available in any language. It mines published texts, unpublished writings and correspondence, state archives, and both recent and older secondary literature to offer reliable explications of nearly everything Comte ever wrote, correlating each moment of his intellectual evolution to the vicissitudes of his personal life, professional situation, and political context. Its extensive notes, bibliography, and numerous discoveries demonstrate considerable patience and care (the word "endurance" comes to mind). This will be a definitive reference for anyone working on Comte or Positivism. While Pickering offers a perspective particularly rewarding for social scientists interested in this neglected founder, the work also has much to offer historians and philosophers of science, historians of France, and general historians of modernity." -John Tresch, The Journal of Modern History.