This book presents a selection of correspondence maintained by the Heidegger brothers between 1930 and 1949, where they discuss the burning political and social theme of their convulsive era. Martin had a very high regard for his younger brother Fritz, who enjoyed similar intellectual gifts and had developed an autonomous thought: on the political plane, Fritz was more critical of National Socialism than Martin. Throughout their lives they both maintained a close union, both family and intellectual, and proof of this is their intense epistolary relationship. In addition to reporting on the image that the brothers have of themselves, this corpus has been carefully selected to shed light on the controversial involvement of Martin with Nazism. Also, its reading raises the following questions: What kind of thinking is right in politics? Does political error affect the philosophical work of whoever commits it? They are difficult questions with no simple answers. However, this text enriches the discussion by showing the positions of both brothers and inducing reflection on the life and work of Martin Heidegger.