This third edition of Collaboration: What Makes It Work—written nearly 25 years after the first edition was published—is an example of the enduring importance of collaboration. Reaction to the first edition, published in 1992, showed that researchers and practitioners alike found it a useful tool. They appreciated its emphasis on providing a practical reference for decision-making that built upon credible, research-based information. The 21st century has brought with it rapid changes and increasingly complex challenges. This third edition in large part responds to the complexity witnessed daily in the authors' work with community, nonprofit, and government organizations. It offers new research and insights paired with practitioner wisdom, adding a “how-to” perspective to help readers put the success factors to work. Nearly 25 years after the first edition was published, it is not just the "how" of collaboration that has changed—who we are collaborating with has changed as well. Today, nearly every collaboration involves some degree of working across difference. Bringing together diverse people, organizations, or sectors in a way that will foster collaborative success requires a unique set of skills. This third edition will ground you in the factors that support successful collaboration and assist you in incorporating those factors into your work.