Large projects, especially in the construction and infrastructure sectors, involve collaborations of many different types, such as built-own-operate, public-private partnership, or competitive dialogue. This monograph details the authors’ research on the types of collaborative projects. The research undertaken for this book responds to the need for a taxonomy of relationship-based procurement approaches, a particular type of project alliancing in need of standardization. Recommendations are made based on interviews with 36 subject matter experts from several countries, as well as an extensive literature review.