Moral Economics examines how societies determine which transactions should be permitted, regulated, restricted, or prohibited when economic exchange conflicts with moral values. Drawing on Alvin E. Roth's work in market design, the book considers controversial markets involving organ donation, reproductive services, sex work, drugs, and other transactions that provoke strong ethical objections. Roth explains how moral attitudes influence the structure and operation of markets and argues that policy choices need not be limited to complete prohibition or unrestricted exchange. Instead, carefully designed rules can balance individual autonomy, social concerns, and protection from harm. Through economic analysis and real-world cases, the book demonstrates how market design can help address disputes in which participants disagree about what should be bought, sold, or exchanged. Written for general readers, policymakers, economists, and students, the work connects economic reasoning with ethical and public-policy debates about the boundaries of markets