The power of reason is extraordinary, and it has made possible an extraordinary range of human achievements. But reason is also fallible, and it has a tendency to run out on us just when things get really interesting. In this fascinating book, John Hendry explains in a straightforward way how reason works together with our other faculties. He explores what it can do for us in different fields of enquiry, how and where it runs out on us, what the practical and political implications are, and how we might reasonably respond. When should we trust the claims of scientists and social scientists, and when should we be more sceptical? What should we make of the claims made by historians, and how can we learn from them? What is the basis of our ethical judgements, and how might we improve them? What kinds of claims are involved in religious belief, how reasonable are they, and how should we, as a society, respond to them?