In the current issue of International Journal of Play Therapy (Volume 17, Issue 1) Athena A. Drews discusses the use of bop bags. She reviews the literature on bop bags and current theories on aggression and aggressive behavior. She notes that there are no empirical studies to support the use of bop bags or other enactments of aggressive behavior in play therapy. She states that cognitive behavioral therapy has proven successful in reducing aggressive behavior. Two books, available at childtherapytoys.com, that provide further information on these and other techniques are Cognitive Behavioral Play Therapy by Susan M. Knell, Ph.D. and Empirically Based Play Interventions for Children edited by Linda A. Reddy, Ph.D., Tara M. Files-Hall, and Charles E. Schaefer, Ph.D.