Thomas D. Cook is Professor of Psychology at Northwestern Unversity where he also holds the position of Director of Training in Social Psychology. He is coauthor of Sesame Street Revisited, Quasi-Experimentation: Design and Analysis Issues for Field Settings and Criminal Victimization of the Elderly. He has also directed, with help, the third volume in Evaluation Studies Review Annual and belongs to the editorial board of Quarterly Evaluation, Evaluation Magazine, Knowledge: Creation, Dissemination, and Utilization.