The library contains:

The reading room

1,000,000 books

2,000 medieval and early modern manuscripts

600 ancestral registers

10,000 maps

4,000 musical scripts

The research library today has approximately 850,000 volumes with collection emphasis on the German literature. Among its special collections is an important Shakespeare collection of approximately 10,000 volumes, as well as a 16th-century Bible connected to Martin Luther.

According to wikipedia.