Book excerpt: This comprehensive Handbook describes the implementation of SEA in 18 countries around the world, as well as a critical analysis of different SEA methodologies. It introduces key SEA principles and the legal requirements of the new European SEA Directive, which became law in 2004, and describes the implementation of SEA in 11 European Union countries, as well as the USA, Canada and New Zealand. This is contrasted with SEA requirements of four developing countries.