De Boeventaalzakwoordenboekje Van Het Bargoensch, of De Taal Van De Jongens Van De Vlakte

''De Boeventaal'' by W. L. H. Köster Henke is a dictionary of the Bargoens, or the language of the boys from the plains, written in the early 20th century. This publication serves as a glossary, organizing various terms and phrases used predominantly in the criminal underworld, particularly among those involved in illicit activities, and it is aimed at aiding law enforcement and officials in understanding this secretive dialect. The opening of the work presents a preface that explains the necessity of such a dictionary due to the prevalence of a unique language among criminals, which is often indecipherable to outsiders. Köster Henke emphasizes the importance of familiarity with this language for police and judicial personnel, as it could significantly impact their effectiveness in handling cases involving criminal suspects and activities. He notes that no comprehensive list of these terms previously existed, and this compilation aims to fill that gap for those in law enforcement and related fields.