This book intends to explain some of the main pieces of Heidegger's theoretical puzzle in order to highlight the position that categories such as "event", "politics", "history" and "truth" acquire in his philosophical journey. Heidegger's thought is an expression, objection and corollary to an era whose essence is the concealment and unconcealment of the political in the margins of legal and institutional politics, that is, under the coordinates of the liberal system that would try to displace political conflict. . When the discourse (politics) and the contingent (the political) come into tension, the latter necessarily reveals itself, emerging with all its substantial, radical and contradictory power. To this day, many thinkers for or against observe Heidegger's philosophy and politics as an eclipse, as if they were the moon and the sun approaching each other, but they lose sight of the shadow that causes the eclipse. Here we try to reveal that shadow that is impossible to observe because it is above us, it covers us and, in the author's words, only thought will allow us to account for it.