Volume 36, Number 2, 2001 Contents: S.P. Reise, N. Duan, Introduction to the Special Issue on Multilevel Models. D. Livert, D. Rindskopf, L. Saxe, M. Stirratt, Using Multilevel Modeling in the Evaluation of Community-Based Treatment Programs. S.C. Carvajal, E. Baumler, R.B. Harrist, G.S. Parcel, Multilevel Models and Unbiased Tests for Group Based Interventions: Examples From the Safer Choices Study. I. Plewis, Explanatory Models for Relating Growth Processes. J.B. Hoeksma, D.L. Knol, Testing Predictive Developmental Hypotheses. J.L. Krull, D.P. Mackinnon, Multilevel Modeling of Individual and Group Level Mediated Effects. S. Rabe-Hesketh, T. Toulopoulou, R.M. Murray, Multilevel Modeling of Cognitive Function in Schizophrenic Patients and Their First Degree Relatives.