Martin Heidegger (b. 1889–d. 1976) is a central figure in 20th-century philosophy. Especially in his early works, most notably Being and Time (1927), Heidegger critically continues the tradition of phenomenology inaugurated by Edmund Husserl (b. 1859–d. 1938). Heidegger’s philosophy has been a major influence on a number of important philosophers in their own right, including Hans-Georg Gadamer (b. 1900–d. 2002), Maurice Merleau-Ponty (b. 1908–d. 1961), Hannah Arendt (b. 1906–d. 1975), Paul Ricoeur (b. 1913–d. 2005), Michel Foucault (b. 1926–d. 1984), Jacques Derrida (b. 1930–d. 2004), and Richard Rorty (b. 1931–d. 2007). His work has also impacted other disciplines, such as theology, literary and cultural studies, art theory, and the theory of architecture. Heidegger is primarily known for his work in metaphysics and existential philosophy, but he has also made much-discussed contributions to a wide range of philosophical topics, including the study of numerous authors from the history of philosophy. The German edition of his collected works (Gesamtausgabe, or GA) includes published writings, lecture courses, seminars, and manuscripts. Once completed, it will include 102 volumes. To manage this rich material, Heidegger’s philosophy is often divided into different periods. Although how to demarcate these periods is itself a matter of scholarly debate, Oxford Bibliographies divides his work into an early, middle, and later period. This entry treats the middle period of his thought (roughly 1933–1945). It coincides with the rise to power of the German National Socialist Party, in which Heidegger was involved as rector of the University of Freiburg, the Second World War, and the Holocaust. Although Heidegger rarely addresses these events directly, this period in particular should not be considered without taking into account these events and the dominant ideologies of the time. Heidegger’s major concerns during this period are with the experience of art, the philosophy of history, and the history of Western philosophy in particular. Heidegger gives a few important lectures and lecture series during this time that were later edited. These should be the starting point for any reading. The major body of his writing during this period, however, consists of manuscripts, notes, and course materials, which are more difficult to assess. In using this bibliography, be sure to also check the entries on the early and later period of Heidegger’s works. Although the focus of Heidegger’s philosophical concern shifts, many themes continue to be relevant throughout his works. Often, scholars writing on Heidegger take into account his development as whole, and relevant literature may be treated in another entry. This bibliography aims to be inclusive with regard to schools of thought and interpretations of Heidegger. It is not exhaustive but rather an attempt to identify useful starting points for individual study within the more recent literature on Heidegger.