The contemporary importance of A. N. Whitehead (1861–1947) lies in his direct yet productive challenge to the culture of thought inherent in modernity, a challenge that suffuses science, social theory and philosophy alike. Unlike some of the more destructive aspects of postmodernism and poststructuralism, Whitehead’s diagnosis of the conceptual fault lines of the modern era does not entail a passive relativism. Instead, he calls for a renewal of our concepts, offering a positive, philosophical approach based on becoming, relativity, and a reconception of subjectivity and the social. This book outlines Whitehead’s philosophy, using it to reorient a range of specific questions and topics within contemporary social theory.