What is epistemology or 'the theory of knowledge'? What is it really about? Why does it matter? What makes theorising about knowledge 'philosophical'? Why do some philosophers argue that epistemology - perhaps even philosophy itself - is dead? In this exciting and original introduction, Michael Williams shows how epistemological theorizing is sensitive to a range of questions about the nature, limits, methods, and value of knowing. He pays special attention to the challenge of philosophical scepticism: does our 'knowledge' rest on brute assumptions? Does the rational outlook undermine itself? Williams explains and criticises all the main contemporary philopsophical perspectives on human knowledge, such as foundationalism, the coherence theory, and 'naturalistic' theories. As an alternative to all of them, he defends his distinctive contextualist approach. While accessible to the undergraduate and general reader, this book contains Williams' own original ideas and is essential reading for all philosophers concerned with the theory of knowledge.