Martin Buber’s The Question to the Single One appeared in Nazi Germany at a time, when collectivism in its totalitarian forms was at the height of its development. On one hand this little book is an immediate reaction to the social-political situation in inter-war Europe. On the other hand it is a consideration of the anthropological question of the modern man from the point of view of dialogical personalism. The paper focuses on Buber’s critique of both the individualistic and collectivistic doctrines of ethical relativism. It examines also his category of the “single one in responsibility” as a response to both doctrines.