This volume brings together original essays by scholars working on a diverse range of empirical issues, but whose work is in each case informed by a 'historical institutional' approach to the study of politics. By bringing these pieces together, the volume highlights the methodological and theoretical foundations of this approach and illustrates the general contributions it has made to comparative politics. The essays demonstrate the potential of the approach to illuminate a broad range of issues such as how and why institutions change, how political ideas are filtered through institutional structures in the formation of specific policies, and how institutional structure can have unintended effects on the shaping of policy. The reader is provided with both a thorough understanding of the method of analysis and an overview of the theoretical underpinnings of the approach.