Abstract During the World Wars, almost all German military libraries were destroyed or suffered heavy losses. One of the rare collections to have survived in its original form is the Weimar military library at the Duchess Anna Amalia Library. It was established about 1630 with books seized by Duke Bernard of Saxe-Weimar in the Thirty Years’ War. After 1787, when Duke Carl August of Saxe-Weimar-Eisenach took command of a Prussian regiment, the collection grew rapidly. Originally a department of the main library, it was separated from it in 1804. During the French Revolution and the Napoleonic Wars, the Weimar military library became a space of universal knowledge: apart from books, it also contained maps, globes, manuscripts and models of fortifications, holding about 15,000 items altogether. After Prussia’s defeat by Napoleon, Weimar was a social and literary centre for the military reformers of 1807-1813 who used and influenced the library. Since 1824, the collection has been kept in the library’s medieval tower. The shelving system goes back to ideas of Carl August and Johann Wolfgang Goethe. The collection is not limited to military literature, but is encyclopaedic in nature.