"The goal of this handbook is to provide guidance to practitioners and organizations interested in evaluating mental health prevention and early intervention (PEI) programs. In the course of developing an evaluation plan for a series of PEI programs implemented statewide by the California Mental Health Services Authority (CalMHSA), we found many resources that discussed general approaches to evaluating mental health programs and policies but few that discussed how to tailor an evaluation approach to mental health PEI activities in particular. PEI activities may require different evaluation strategies than treatment interventions do. First, the activities being administered are different in that they are not clinical interventions. Indeed, PEI activities are highly diverse and provided in many different types of nonclinical settings. Thus, the process outcomes that are used as indicators of successful implementation tend to look different for PEI interventions." (Introduction)