Paul Feyerabend (1924-1994) was one of the foremost twentieth-century philosophers of science. Although he attained infamy by embracing cultural relativism and by providing a searing critique of the claims of science, there has been, to date, no comprehensive critical study of the major themes in Feyerabend’s philosophy. This book rectifies that situation. The book traces the evolution of Feyerabend’s thought, beginning with his attempt to graft insights from Wittgenstein’s conception of meaning onto Popper’s falsificationist philosophy. The component parts of Feyerabend’s ‘model for the acquisition of knowledge’, the normative aspect of his project, and its roots in a Popperian conception of epistemology, are identified and critically evaluated. Feyerabend’s early work emerges as thoroughly post-Popperian, rather than as a contribution to the historical approach to philosophy of science with which he is usually associated. In his more notorious later work, notably the 1975 book Against Method, Feyerabend claimed that there was, and should be, no such thing as the scientific method. This ‘epistemological anarchism’ and Feyerabend’s attendant relativism are examined here in the light of his recognition that Against Method was a collage constructed out of his earlier thoughts. The roots of epistemological anarchism are exposed, and the weaknesses of Feyerabend’s later thesis of incommensurability are brought out. Throughout the book, the influence of Feyerabend’s thought on contemporary philosophers is tracked. The author draws attention to Feyerabend’s exciting but divided legacy. On the one hand, contemporary scientistic philosophers have used his earlier views in a vigorous defence of an uncompromising ‘eliminative’ materialist view of the mind. On the other hand, thinkers influenced by Feyerabend’s later work have begun a humanistic critique of science, scientific myth-making, and scientific claims to knowledge. The book will be of interest to undergraduate and postgraduate students of philosophy, methodology, and the social sciences.