In this introduction to some of the most frequently discussed areas of philosophy, Sir Alfred Ayer made his subject accessible to both the general reader and the student. Among the topics covered are the nature of philosophy, varieties of philosophical analysis, theory of knowledge, status of physical objects, relations between body and mind, character of scientific explanation, theory of probability, elements of logic and the claims of theology. Although it ranges more widely, the book invites comparison with Bertrand Russell's "The Problems of Philosophy".