This comprehensive Handbook shows how Strategic Environmental Assessment (SEA), an important decision support tool for strategies, policies, plans and programmes, is applied globally. It reflects on SEA practices and the advancements made over the past three decades in the development of SEA. Forty-six expert international contributors discuss the conceptual approaches and applications of SEA in 31 countries, examining numerous sectors, including land-use, transport, energy and water. They also explore how SEA is applied at trans-national, national, regional and local levels, and at a range of decision tiers, including in strategy and policy, as well as in plans and programmes. Analysing how different situations of application are systematically approached, chapters provide a critical insight into the objectives of SEA and the range of methodologies that are available. Taking a forward-thinking approach, the Handbook also identifies key trends and prospects for SEA in addition to addressing issues of SEA effectiveness and theory development. This Handbook will be a valuable resource for academics and students of environmental governance and regulation. It will also be beneficial for impact assessment practitioners, environmental NGOs and policy makers in the fields of environment and sustainability.