The notion of Befindlichkeit in Heidegger’s phenomenological way. Heidegger’s phenomenology of Befindlichkeit and the different kinds of affection was initiated still before Being and Time, and developed in its essential features till the end of the 1930’s. The current paper argues that, since its very origins in a philosophical framework, back to the translation of the affectiones in Augustine, the notion of Befindlichkeit sets the beginning of a structural understanding of existence - displayed both at the ontological levei of Grundstimmungen (such as anguish, boredom or reservedness), and at the ontic level of different factual Stimmungen. Any comprehensive analysis of those affections counts on a tripie background with a Wovor, a Worum and the full-fledged exercise (Vollzug) of such and such affective understanding. In Being and Time this analysis is dedicated to fear, in its different nuances. But this phenomenon was already dealt with in Heidegger’s Lectures on Augustine (1921) and will reoccur in the Beiträge (1936-38). A reading of this conceptual evolution will here ground a defense of the phenomenological character of Heidegger’s way of thinking.