Being and Time

Heidegger's main work, published in 1927 and left unfinished: only the first two divisions of a planned six appeared. It reopens the question of the meaning of Being, which Heidegger thinks philosophy has forgotten since the Greeks. Because we are the beings for whom our own Being is an issue, he begins with an analysis of human existence, which he calls Dasein. Division One describes Dasein as being-in-the-world: we first meet things as ready-to-hand equipment, like a hammer in use, not as present-at-hand objects; we mostly live as 'the They' (das Man) live; and our basic structure is care (Sorge). Moods disclose the world, and anxiety reveals our thrownness into it. Division Two turns to being-towards-death, conscience, guilt and resoluteness, distinguishing authentic from inauthentic existence, and finally shows that care is grounded in temporality and historicality. The vocabulary is new and hard, but many analyses are concrete.

It changed how philosophers think about everyday practice, mood, death and time, and lies behind existentialism, hermeneutics, Sartre and Arendt, and later work on embodied cognition.