Why is another theory of evaluation needed? The paradigm wars have left a void in their wake. A new theory, firmly grounded in a credible philosophy of science, is needed to guide practice. The aim of this volume is to provide a new theory that captures the sensemaking contributions from post-positivism and the sensitivity to values from constructivist traditions. The theory presented here is not a slap-dash synthesis of the competing paradigms--it is a new approach. Some of the contributions of the realist theory of evaluation are (1) providing a basis for principled discovery as we oscillate between explanations and data; (2) using explanation as a means for extrapolating findings from one evaluation to other settings; (3) viewing all methods, both quantitative and qualitative, as aids to sensemaking that have strengths and flaws; (4) connecting evaluation practice with the ultimate goal of most program evaluation--social betterment; and (5) balancing the focus of the evaluation between sensemaking and value inquiry. This is the 78th issue of the quarterly journal New Directions for Evaluation.