First Published in German in 1981 as Grundbegriffe (volume 51 of Heidegger's collected works), this translation of Martin Heidegger's lecture course at the University of Freiburg in the winter semester of 1941 offers a concise introduction to new directions in the philosopher's later thought. Shifts in Heidegger's thought from the problem of the meaning of being to the question of the truth of being are evident in this outstanding translation.