The Georg Eckert Institute was established by the federal state of Lower Saxony in 1975 with a mandate to carry out international research into textbooks and to develop recommendations for education policy-makers and publishing houses. The history of the Institute, however, can be traced back to 1951, when Georg Eckert founded the International Institute for Textbook Improvement at the Kant Teacher Training College in Braunschweig, with the aim of strengthening international understanding. The textbook library was at the core of this work from the outset. The research library at the GEI today contains the world’s largest international collection of textbooks and teaching materials for humanities and social studies subjects. The book, now in its second, revised edition, illustrates the contributions made by the GEI to textbook revision and how it has contributed fundamentally to the development of textbook and educational media research. This is an academic field that not only focusses on textbooks but also on digital educational media and the methods used to research them.