This working paper makes the basic case for supporting and developing advocacy. It explores the advocacy sector in London and the government's growing interest through a literature review, document analysis, and explorative questionnaire to advocacy providers, in-depth interviews with key stakeholders, and focus groups with a range of community leaders. It also draws sector and policy views together and makes recommendations about the way forward. The paper is part of 'Putting Health First', a programme of work set up by the King's Fund to explore the idea of a health system that gives priority to promoting health and reducing inequalities, as well as delivering health care services. [Summary]