This paper presents an overview of historical and recent developments in teachers' continuing professional development in the United Kingdom. It surveys the varieties of CPD available to teachers and examines their impact and value in terms of contribution to teachers' development. It also examines the underlying paradigms and discourses of teaching which underpin, often tacitly, the kinds of CPD offered by schools, local education authorities (LEAs)s, advisory services where these exist, commercial organisations providing government-backed training, and university education faculties. The nature of each kind of in-service education is considered in the context of the discourse of teaching within which it is grounded. Views of the unique role of the universities in providing in-service teacher education are presented and the authors examine the key issues related to university- based CPD, such as the possible theory/practice divide, the clash of discourses of teaching, and the role of research in continuing professional development. Finally the paper considers alternative models of continuing professional development in relation to Harland and Kinder's typology of CPD outcomes.