English scientist Stephen Rose, specializing in brain biochemistry, considers the most fundamental scientific problem to solve the question of what life is. You can try to get an answer to this question only by mastering a huge amount of human knowledge and, above all, a relatively young science - biochemistry, to which this small popular science book is devoted. The author introduces the reader to the chemical composition of a living cell, with the processes taking place in it, their relationship and methods of regulation.