To this day, well over 800 documents from before the year 1000 are kept in the Abbey Archive of St. Gallen. It is an extraordinary body of original documents that is subjected to a systematic diplomatic investigation for the first time in this book. In the first three sections of the book, fundamental aspects of the document system in early medieval Alemannia are dealt with and the external and internal characteristics of the St. Gallen documents (i.e. writing materials, written forms, graphic symbols, document forms and formulas) are examined in detail. The following sections are based on this formal-diplomatic basic analysis, in which first the development of the monastic (St. Gallen) document system is followed and then the traces of non-monastic, local writing activities are followed. In this way, the coordinates of a historical documentation landscape in Alemannia are gradually marked out.