This article sheds new light on the Swedish comprehensive school reform implemented in the 1960s (the Grundskolan reform) and the four decades preceding the reform. This reform was typical for the Nordic countries. The presented study concerns reforms in mathematics education and how change was initiated and driven before and during the comprehensive school reform. The analysis has a focus on the role of textbooks in educational governance. The analysis is based on Bourdieu’s field theory and concerns how a new way of preparing and driving reforms of school subjects restructured relationships between the state, textbook producers, and teachers. This article is mainly a synthesis of results from several previous studies on governance of Swedish mathematics education. The analysis reveals not only a new characteristic of the comprehensive school reform (swift and radical rather than slow and successive), but also a bottom-up movement in the school system, which has been commonly understood as top-down, very centralised, and slow moving. The results of the analysis help explain why the Swedish comprehensive school reform gained early acceptance and momentum. Another contribution of this article concerns historical textbook research, particularly regarding how fundamental changes in authorship of textbooks (from visible individual authors to anonymous collectives) can be related to educational governance and changes in power structures.