The paper assesses the rationale, contributions, structure, and challenges of the field of development ethics. Processes of social and economic transformation involve great risks and costs and great opportunities for gain, but the benefits, costs, and risks are typically hugely unevenly and inequitably distributed, as is participation in specifying what they are and their relative importance. The ethics of development examines the benefits, costs, risks, formulations, participation, and options. The paper outlines a series of ways of characterizing such work, arguments (...) for and against its importance, and some of its major sources and contributions, especially from the interdisciplinary stream of work represented over several decades by Denis Goulet. Definitions are diverse since the work covers many different intersections of practice and theorizing, at multiple levels. The paper considers and replies to arguments against discussing development ethics: the claim that it involves only endless proliferation of different opinions, is an expensive luxury that undermines long-run development, is superfluous if one already works with the capability approach or the human rights tradition, or never has influence. Finally, it presents suggestions for how development ethics thinking can have increased impact, with reference to incorporation in policy analysis and planning methods, professional codes and training, and to its intellectual location and communication strategies. The field should articulate the methodological pragmatism which much of it has adopted, consistent with its required role as a practice-oriented interdisciplinary meeting ground. (shrink)