This third volume of Paul Feyerabend's philosophical papers, which gathers together work originally published between 1960 and 1980, offers a range of his characteristically exciting treatments of classic questions in the philosophy of science. It includes his previously untranslated paper 'The Problem of Theoretical Entities', and the important lecture 'Kwledge without Foundations', in which he develops the perspective on early philosophy and science put forward by Karl Popper. Other themes discussed include theoretical pluralism, the nature of scientific method, the relationship between theory and observation, the distinction between science and myth, and the opposition between 'rationalism' and relativism. Several papers from the 1970s detail his increasing preoccupation with the social status of science and with the decline (as he perceived it) in quality within the philosophy of science itself. The volume is completed by a substantial introduction and a comprehensive list of Feyerabend's works.