This book, one of the most frequently quoted works on Martin Heidegger in any language, belongs on any short list of classic studies of Continental philosophy. Richardson explores the famous turn in Heidegger's thought after Being in Time and demonstrates how this transformation was radical without amounting to a simple contradiction of his earlier views. In a full account of the evolution of Heidegger's work as a whole, he provides an illuminating account of divergences and continuities in Heidegger's philosophy in light of recently published works. Includes as a preface the letter that Heidegger wrote to Richardson and a new writer's preface and epilogue.