Why are school systems structured differently across countries? The Politics of Comprehensive School Reform examines this question through an in-depth analysis of school politics in Germany and Norway during the post-war period of educational expansion. Using a Rokkanian theoretical framework, the book argues that school politics can only be understood in light of the cleavages, or political divides, that shape actors' interests, ideologies, and inclinations for who they want to cooperate with – or not. The book analyzes cross-cutting cleavages connected to religion, geography, language, anticommunism, and gender, and demonstrates how Norwegian social democrats and German Christian democrats built successful coalitions by mobilizing support from different social groups. Extensively researched and expansively applicable, this book contributes to the interdisciplinary literature on the politics of education, and to the field of comparative welfare and education regime research. This book is also available Open Access on Cambridge Core.