The fortress plans of the Prussian War Ministry are being re-recorded and inventoried here for the first time according to modern guidelines. Of the approximately 11,000 individual sheets, around 8,600 are attributable to 55 Prussian fortresses and smaller fortifications, around 2,450 to twelve federal or imperial fortresses and the rest to fortifications in German states and abroad. The plans were mainly drawn in the 19th century, but in individual cases also go back further or into the period of the First World War. They show floor plans of complete fortifications as well as parts of fortresses, detailed construction drawings of fortifications and individual structures, but also topographical maps of the fortress surroundings, city plans and drawings of traffic systems. The volume concludes with a glossary of the fortress terms that appear in the inventory, as well as indices for the names of the person responsible, the place and the person.