This text draws on research undertaken for the Joseph Rowntree Foundation on Development Impacts and Development Obligations to provide an account of the developing role of agreements in dealing with the impact of development. The first part reviews the policy, legal, planning and development context. The second part reviews contemporary practice. The third part reviews future developments. The authors bring their experience of both planning theory, practice and law and their empirical work to this major statement on an important area of planning practice. The focus is primarily on England, but the British experience is set in the wider context of experience elsewhere.