Based on Robert Heilbroner's New York Public Library/Oxford University Press Lectures given in May 1994, this work focuses on the question of humankind's future. The first lecture treats depictions of the future that dominated all cvilizations in the 17th century. The second lecture deals with the early 19th and 20th centuries - an age of buoyant secular expectation which provided material improvement for all human kind. The third lecture shows that pessimism about the future has returned and that there is little turning to religion for solace.