Biller, T. Die mittelalterlichen Stadtbefestigungen im deutschsprachigen Raum. Ein Handbuch. 2 Bände

Whether a powerful free imperial city or a small sovereign town - all of these settlements had one thing in common, and it was the fortification, the city wall. Thomas Biller's work is the first ever systematic and at the same time comprehensive overview of medieval town fortifications.
In a systematic section, Biller deals with all aspects of medieval town fortifications: from the pre- and early forms to the fully developed fortifications of the High Middle Ages to the end and demolition of the town walls in the artillery age. It describes all elements of urban fortifications: Wall, all forms of guard and gate towers, moats, land defences etc. The aspects of financing, construction and maintenance are also important. A second regional section describes all the town fortifications in the German-speaking area that can still be documented, from Pomerania and the Order of Prussia to Austria, Switzerland and the remaining parts of the Empire.