The monograph presents a text-critical edition of the historical source, i.e. the register book of the first Protestant congregation of Ljubljana from the last quarter of the 16th century, which is also considered to be the oldest surviving register book in the mainland part of present-day Slovenia.

The text provides a wealth of invaluable genealogical information about the townspeople of Ljubljana, their family connections and occupations, the nobility and other inhabitants of Carniola, as well as members of the Protestant faith who came to Ljubljana from nearby lands.

The introduction outlines the reasons for the beginning of the registry entries, the fate of the registry after the end of its »active use«, and the probable cause and timing of the destruction of almost five-sixths of the entire registry. The main body of the monograph is a transcription of the register, with a preliminary explanation of the editorial principles, which concludes with an extensive index of names, places and objects.