Manfred Max-Neef - Social Sustainability and Basic Human Needs

A Chilean economist, taught at University of California - Berkeley, in the 1960s, developed a framework for sustainable social development centerd on nine fundamental and universal human needs, distinguised from the things and methods used to satisfy those needs, which vary from place to place, culture to culture, time to time.

This framework for defining basic human needs, as related to the Brundtland Report's definitiion of sustainable develoment (paraphrased: meeting the human needs of the present without reducing the capacity to meet them in the future), is being used by The Natural Step (TNS) in their ongoing effort to develop their Framework for Strategic Sustainable Development (see a summary by the Alliance for Sustainbility with links to TNS).

See this google search for a quick overview.

Also, wikipedia.