This chapter serves as an introduction to the book and addresses how the study will go about investigating the institutionalization of age-grading as a characteristic feature of modern school organization. This practice of allocating schoolchildren is manifested in the correlation of pupils’ achievement levels and their chronological age. The section delineates the object of investigation and introduces the methodological approach as well as the sources and selected case study, before giving an outline of the subsequent book chapters. The final part of the introduction reflects upon the particular writing style of the text, which is composed in an inter-connected way that gives the reader the opportunity to navigate through the networks developed in the text in a more explorative, individual fashion.