A new, full-colour edition of the best-selling Theory of Knowledge for the IB Diploma. Now available as a full-colour version, this is a comprehensive, best-selling title for the Theory of Knowledge course in the IB Diploma Programme. It is also useful for students following other critical thinking courses. The fundamental question in Theory of Knowledge is 'How do you know?' In exploring this question, the author encourages students to ask relevant questions, use language with care and precision, support ideas with evidence, argue coherently and make sound judgements.