Professor Bartlett has given his celebrated one-hour lecture, Arithmetic, Population and Energy: Sustainability 101 over 1,600 times to audiences with an average attendance of 80 in the United States and world-wide. His audiences have ranged from junior high school and college students to corporate executives and scientists, and to congressional staffs. He first gave the talk in September, 1969, and subsequently has presented it an average of once every 8.5 days for 36 years. His talk is based on his paper, Forgotten Fundamentals of the Energy Crisis , originally published in the American Journal of Physics, and revised in the Journal of Geological Education. Professor Al Bartlett begins his one-hour talk with the statement, The greatest shortcoming of the human race is our inability to understand the exponential function .