According to a conservative estimate, Bruno Schröder's library contained around 70,000 books. Compared to the municipality's only public library, a two-room shop with 4,500 titles, Bruno Schröder's private library was almost sixteen times larger.

There, the shelves are integrated into the sloping roof in such a way that the books line the entire interior surface of the roof. "Insulation," one of my conversation partners remarks, "that Robert Habeck would wish for in every house."

According to an estimate by an antiquarian bookseller whom Renate Abeln guided through the bookshop, Bruno Schröder invested between 800,000 and one million euros in books over his lifetime.

The largest pri-vate collections reached 3,000 or 4,500 volumes in the late sixteenth century and tens of thousands of volumes in the mid- eighteenth century. (Hans Sloan owned 45,000 books and 4,000 manuscripts at his death in 1753.)194