Convincing arguments that knowledge needs to be 'brought back' to the curriculum, and the attention of curriculum researchers, and a growing emphasis on international educational comparisons, has resulted in a 'crisis' in curriculum studies. Building on seminal work in the sociology and philosophy of education in order to develop new foundations for curriculum study, and using the importance of 'transactions' as the context for understanding knowledge in the curriculum, this book suggests a rapprochement in the field around the idea of curriculum knowledge as both constructed and real. This book was originally published as a special issue of The Curriculum Journal.