This introduction sets out the objectives, topic, method and structure of this thesis. I describe philosophical folk psychology and the roles that it is presumed to play in action choice, interpersonal understanding and reason giving. Philosophical folk psychology – particularly when expressed as belief-desire psychology – is suggested by some as a way to describe all three of these phenomena under a single model. I argue, however, that this comes at the cost of a number of unwarranted commitments which give rise to philosophical problems. I introduce a handful of influential thinkers who have advanced folk psychological positions and also some contemporary examples of philosophers addressing problems arising directly from it. I then introduce the diagnostic-therapeutic intent of this thesis, grounded in a reading of Wittgenstein’s approach to philosophy through the later work of Gordon Baker. Thereafter I set out the two-part structure of the thesis and briefly outline the chapters.