Al Bartlett is a retired Professor of Physics who joined the faculty of the University of Colorado in Boulder in September 1950. His B.A. degree in physics is from Colgate University (1944) and his M.A. and Ph.D. degrees in physics are from Harvard University (1948), (1951). In 1978 he was national president of the American Association of Physics Teachers. He is a Fellow of the American Physical Society and of the American Association for the Advancement of Science. In 1969 and 1970 he served two terms as the elected Chair of the four-campus Faculty Council of the University of Colorado. In the late 1950s Al was an initiator of the citizens' effort to preserve open space in Boulder, and this ultimately led to the establishment of the City of Boulder's Open Space Program which (1998) has purchased over 26,000 acres of land to be preserved as public open space. He is a founding member of PLAN-Boulder County, an environmental group for the City and County. Since the late 1960s he has concentrated on public education on the problems relating to and originating from population growth. Since 1969 he has given his lecture, "Arithmetic, Population, and Energy" over 1300 times to audiences of all levels from coast to coast. More recently he has written on sustainability, examining the widespread misuse of the term, and examining the conditions that are necessary and sufficient for sustainability in any society.