The text of one of the most significant works of Martin Heidegger is offered to the Russian reader in full for the first time. Its introductory part was published in 1989 in the journal “Problems of Philosophy” in a joint translation by V.V. Bibikhin and A.V. Akhutin and even then aroused enormous and completely justified interest. Now the problems that were only posed by the great German philosopher in the initial chapters receive detailed consideration and development. The book arose on the basis of a lecture course given by Heidegger in Freiburg in the winter semester of 1929-30, i.e. in direct connection with the topic “ Being and Time is the fundamental work of the early period of his philosophizing, and is of particular interest in a double connection. On the one hand, it contains a detailed analysis of boredom as the fundamental mood of modernity; on the other hand, it offers an equally detailed definition of the essence of the organism and life - in “Being and Time” this problematic was only outlined by Heidegger. The book was translated by A. P. Shurbelev in constant collaboration with A. V. Akhutin. The previously published introductory part, on which the late V.V. Bibikhin worked, was left unchanged by the publishing house and accepted as a guideline and model for completing the work he began.