Eighteen leading philosophers offer critical assessments of Timothy Williamson's ground-breaking work on knowledge and its impact on philosophy today. They discuss epistemological issues concerning evidence, defeasibility, scepticism, testimony, assertion, and perception, and debate Williamson's central claim that knowledge is a mental state. The volume appears suitable for an audience of (mainly postgraduate) students and scholars of philosophy who are already familiar with Williamson's knowledge-first epistemology but look for clarifications, further explanations, or aim at a critical assessment of it in the light of more recent philosophical reflection. The book turns out to be a very valuable tool with respect to these aims. ... intreguing and valuable.