This book is the first comprehensive critical study of the work of Paul Feyerabend, one of the foremost twentieth-century philosophers of science. The book traces the evolution of Feyerabend's thought, beginning with his early attempt to graft insights from Wittgenstein's conception of meaning onto Popper's falsificationist philosophy. The key elements of Feyerabend's model of the acquisition of knowledge are identified and critically evaluated. Feyerabend's early work emerges as a continuation of Popper's philosophy of science, rather than as a contribution to the historical approach to science with which he is usually associated. In his more notorious later work, Feyerabend claimed that there was, and should be, no such thing as the scientific method. The roots of Feyerabend's 'epistemological anarchism' are exposed and the weaknesses of his cultural relativism are brought out. Throughout the book, Preston discusses the influence of Feyerabend's thought on contemporary philosophers and traces his stimulating but divided legacy. The book will be of interest to students of philosophy, methodology, and the social sciences.