Heidegger's notes in the so-called "Black Notebooks" show that his engagement with National Socialism was deeper and lasted longer than one would have assumed based on earlier sources. While Heidegger's more strictly philosophical texts from the 1930s and early 1940s are almost free of ideological and political statements, the "Black Notebooks" from those years contain a disturbing mixture of philosophical reflections, political declarations, and aggressive anti-Semitic remarks. How the relationship between philosophy and ideology should be assessed in this context will occupy Heidegger research for a long time. The completely revised seventh edition of Günter Figal's introduction invites critical revision.