This guidance manual provides support in using Integrated Assessment as a tool for mainstreaming sustainability into policymaking processes (policies, plans and programmes). In doing so, it uses international experiences in the area of Strategic Environmental Assessment (SEA) and Integrated Assessment (IA) during recent years, and in particular includes UNEP’s country-level experiences of Integrated Assessment of trade-related policies, with a focus on the agricultural sector, undertaken over the last ten years in a large number of countries.