Defense economics is now an established part of economics. This article reviews its achievements as represented by papers published in the research journal Defense and Peace Economics. The range of topics in the journal is reviewed, especially since 2000, and major gaps in coverage are identified. A changing research agenda reflects new developments such as terrorism and international peacekeeping. Gaps remain such as the need for good quality case studies of conflict (e.g., Iraq) and of major weapons projects (e.g., F-22 Raptor). Some challenges are outlined, namely, the choices resulting from the defense economics problem, the U.K.'s nuclear weapons policy, project case studies (e.g., Eurofighter Typhoon), military outsourcing, and data problems.