Heraclitus is the first English translation of Volume 55 of Martin Heidegger’s Gesamtausgabe. This important volume consists of two lecture courses given by Heidegger at the University of Freiburg over the Summers of 1943 and 1944 on the thought of Heraclitus. These lectures shed important light on Heidegger’s understanding of Greek thinking, as well as his understanding of Germany, the history of philosophy, the Western world, and their shared destinies.