Developmental Evaluation Exemplars: Principles in Practice is a comprehensive collection edited by Michael Quinn Patton that showcases twelve high-quality case studies in developmental evaluation (DE). These case studies provide deep insights into how DE is applied to evaluate innovative initiatives in complex and dynamic environments across various fields and international settings. The book, which was published on October 21, 2015, by The Guilford Press, offers a rare glimpse into the practical aspects of conducting DE, highlighting the roles that must be fulfilled and the expected outcomes. Each case study is introduced with an incisive overview provided by the editors, and the book also addresses common questions about DE, synthesizes key themes and lessons learned from the examples presented, and outlines eight essential principles of DE.