The purpose of this guidebook is to help organization and agency leaders set goals and develop measures to track their progress and achievement of 2Gen change. The introduction begins with definitions of key terms used throughout the guidebook, then provides a brief history of the 2Gen approach and describes lessons learned that inform today’s “2Gen 2.0” efforts. It continues with discussions of the 2Gen continuum of policy and systems change, the role of organizational change in achieving parent and child outcomes, and stages of organizational collaboration.