This chapter attempts to draw out comparisons and make sense of devolution as a UK-wide phenomenon. Devolution has taken a variety of forms at different times in different parts of the UK. A key aim of the chapter is to describe these varieties and explain why no common form of devolution emerged. Devolution may be a form of constitutional development but it has always been linked to wider socio-demographic and economic developments as much as to the sense of collective identities. Some interpretations emphasize the role of national identity in the demands for devolution in Scotland and Wales while others lay more emphasis on differences in political preferences that stimulated demands for self-government. No understanding of the politics of devolution is complete without an appreciation of the roles of identity, the party systems, political and public policy preferences, and how these changed over time.