Terror and Dread: The Significance of “The Unfamiliar” in the Ontology of Martin Heidegger’s Being and Time The article is dedicated to the concept of fear (Furcht) as mode-of-attunement in Martin Heidegger’s ontological analysis as presented in Being and Time. Unlike the much discussed anxiety (Angst), fear for most of the time remains a marginal concept in Heideggerian studies. The article focuses specifically on fear and the three graded forms that it may assume (alarm, dread, terror) which are dependent upon the actual cause for fear. The discussion turns to the possible causes, distinguishing a fundamental polar division into the recognizable and the unfamiliar. The unfamiliar is then brought into proximity with a related concept, that of the uncanny, and both are analyzed in terms of the existential fore-structure of understanding with the intention of demonstrating the possible consequences of the unfamiliar upon Dasein’s being-in-the-world.