Sustainability has dominated the policy discourse for at least five decades, with its most popular articulation to be found in the Brundtland report in 1987 (World Commission on Environment and Development, 1987). Today, Agenda 2030 and the Sustainable Development Goals (SDGs) (UN, 2015) have renewed concern with legal perspectives on sustainability, for, at the European and domestic levels, sustainability and sustainable development are prominent in policy, and also in legally binding instruments. Examples include Article 3 of the Treaty on EU, which makes sustainable development a goal for the Union, and the environmental integration principle in Article 11 of the Treaty on the Functioning of the European Union. Sustainable development was mainstreamed into the Europe 2020 strategy in 2010 (EU, 2010), it is included in the 7th Environmental Action Programme and more recently a Communication from the Commission considers the steps for a sustainable European future integrating the SDGs in the European policy framework (European Commission, 2016). At the domestic level, in the UK sustainable development was introduced as the main aim of the Environment Agency with the Environment Act 1995 and today there are a number of statutes incorporating sustainable development as an aim or duty (such as the Marine and Coastal Access Act 2009 and the Well- being of Future Generations (Wales) Act 2015).

Although the policy roots of sustainability date back over 50 years and the sustainability rhetoric today is more visible than ever in the SDGs, the meaning of sustainability and its relationship with law remain highly contested and complex. Indeed, the mainstreaming of sustainable development has not meant homologation. Distinct legal fields, p ermeated by s ustainability, e ngage with s ustainability differently. This book reflects on the multiple intersections of law and sustainability in a variety of fields. Only by considering sustainability through different l egal s ources a nd fi elds is it po ssible to provide a more comprehensive analysis of the way in which sustainability discourses push certain legal boundaries and the way in which the law itself pushes sustainability in multiple directions.