Ullstein is one of the most important publishing houses in german history. Founded in 1877 it played an important role in the newspaper-market in the early 20th century, and as a modern publishing house of fiction for the mass market. (The house still exists today, but not with the same relevance.) There was also an “archive and library” (Archiv u. Bibliothek), were this book stood ones, apparently in the 1960s.
The stamp consists of two parts/stamps. One, on the bottom, is just a the name of the institution, highlighting “Ullstein” in a bold font, and the amendment GmbH (limited liability company) and the name of the institution in the publishing house. The style and the blue ink suggests a administrative act more than a library (like a running number stamp on a file). The stamp above, with it’s bold, black border and it’s demineering appearance, on the other hand, creates the impression of a confident institution. It includes a space for the signature of the book (which, by this system, can not really be changed anymore). It is a really seldom used system of library stamps.