Nathan H. Azrin, PhD (1930-2013) was the father of four children and a leading authority on the psychology of learning. He received his PhD from Harvard University, was a research associate at the Boston University School of Medicine, and was a lecturer at Harvard’s Psychology Department. The former editor of the Journal of Applied Behavior Analysis and the Journal of the Experimental Analysis of Behavior, he published more than 100 studies in the field of learning and psychological treatment.