Statements of objectives are widely used in international treaties and national legislation and they perform multiple roles. One role is as a communication and public relations tool. Simple, clear and qualitative objectives such as ‘protecting clean air’ communicate to the general public the broad outcome that is intended to be achieved, thereby building public and political support. A second role is as an aid to interpreting treaties and statutes, although this role should not be overstated. A third role is to provide criteria for success in program review as part of the policy cycle. This chapter explores these roles using sustainable development and climate change as two examples of objectives in practice.