A general overview of problems, current activities, and future action related to the human environment is delineated in this United Nations pamphlet. Reviewed first is the challenge facing the United Nations to promote common interest in protecting the earth's life-sustaining essentials. Following this, world scientific and technological strides and their mass consequences are outlined, cited as the evidence or reasons for numerous plans, proposals, and conferences conducted by the United Nations, including the United Nations Conference on the Human Environment. The efforts described represent a sampling of the varied ideas put forth within and outside the United Nations family of organizations. The scope of work underway in the United Nations system is indicated by a summary of activities now being carried out by several of the specialised agencies and bodies of the United Nations. (BL)