This book is a fascinating blend of philosophy, history, biography and detective investigation. It is about a variety of things - this is the assimilation of Jews in Vienna of the fin-de-siecle era, and aberrations of memory under the influence of stress, and a picturesque image of Cambridge, and vivid portraits of eccentric teachers of philosophy, including Bertrand Russell, who played the role of an arbitrator among them. But in the center of the book are the fates of two titan philosophers, Ludwig Wittgenstein and Karl Popper, haughty, irritable and always ready to rush into battle.