This paper discusses why integration is important in doing research for developing policy and practice of sustainable environmental management. The imperative of integration includes environmental, social, economic, and other disciplinary considerations, as well as stakeholder interests. However, what is meant by integration is not always clear. While the imperative is being increasingly enunciated, the challenges it presents are difficult and indicate a long term pursuit. This paper clarifies the different dimensions of integration, as an important preliminary step toward advancing mutual (...) understanding and the development of approaches. The paper identifies the driving forces for integration, discusses when integration is required, categorises forms of integration, and proposes principles to inform research programs and projects. (shrink)