In this additional volume of A History of Philosophy Copleston provides a detailed and objective introduction to Logical Positivism and Existentialism - two highly controversial areas of recent thought.Frederick Copleston was Professor of the History of Philosophy and Dean of the Faculty of Theology at London University. This eleven-volume work is one of the most remarkable single-handed scholarly enterprises of modern times. Volume 11 covers A.J. Ayer, Albert Camus, Martin Heidegger, Karl Jasper, Søren Kierkegaard, Gabriel Marcel, Jean-Paul Sartre and Ludwig Wittgenstein.Between them, the movements of Logical Positivism and Existentialism dominated philosophy in Europe for much of the last century, and the influence they exerted can still be felt today. This book explores the work of many of the most important thinkers of the twentieth century.Brimming with detail and enthusiasm, A History of Philosophy gives an accessible account of philosophers from all eras and explains their works in relation to other philosophers. Each volume is an ideal guide for students studying specific eras and as a set offers a complete and unrivalled overview of the entire western philosophical tradition.