Many congregations find that creating and nurturing small relational groups lead to congregational health and faith development in individuals. Transformational Groups is a book that presents key principles for dynamic small groups. More importantly, this resource asserts that key principles can be measured. The assertion is that they should be measured so that effectiveness can be secured. The authors, Setzer and Geiger, use data from the largest survey of pastors and laypersons ever done on the condition of flourishing small groups. Both authors are associated with LifeWay Christian Resources, one of the world's largest providers of Christian products for congregational life. Chapter 4, titled “Integration,” will help leaders who are starting small groups. Chapter 7, which expounds on the multiplication of groups, will be helpful to those who want to expand their small group work. What behaviors do you want your groups to encourage? What kind of training will lead to the best results? These questions and more are addressed using real life examples. Small groups within congregations are where many learn to deepen relationships with God and others. This book will support congregational leaders who seek to develop and sustain strong small groups.