The book develops those philosophical doctrines, which underline the close relation between human activity and situation. It contains an outline of a phenomenological account of intention, a reconstruction of the reception of the Aristotelian concept of praxis in the philosophy of the 20th century (Heidegger, Gadamer, Ricoeur, Arendt), it analyzes notions of situation and motivation (in Sartre, Ricoeur and Merleau-Ponty), and finally developps a description of basic constituents of the situation of action.