A synthesis of the state of the literature is discussed in this section of the Evaluation Capacity Building (ECB) forum organized around four critical questions: (1) What is ECB? (2) How can we make it happen? (3) How do we know it is happening? and (4) What is its impact? The authors argue that to move the field of ECB forward we need to envision the science of ECB, not as the sole activity of creating new knowledge but in a close congruent and reciprocal relationship with practice. By adhering to a science-practice model, we conduct research that directly responds to and contributes to practice thus creating strong synergies between ECB practitioners and researchers. Research on ECB needs to be informed by real issues happening in practice, and practice of ECB needs to be informed by the new knowledge created. We must strengthen the science to refine our practice and strengthen the practice to refine the science.