The Karl Popper Collection is an archive dedicated to the research on Popper. It is located in the University Library of the University of Klagenfurt in Austria and holds Popper’s books, correspondence, manuscripts and other writings. The material was acquired from the philosopher’s estate in 1995 and since 2000, the documents are available for researchers. The Collection is also open for interested visitors and offers guided tours.
The Karl Popper Collection maintains the “International personal bibliography of Karl R. Popper.” It consists of two documents with associated indices: “Writings of Karl Popper”, a list of Popper’s published works, and “Writings on Popper and His Work”, a list of works published on him since 1932. A new version of the bibliography is released two times per year. The latest versions can be found here and here respectively.
Since 2008, the University of Klagenfurt holds the rights concerning Karl Popper’s work. Since that time, the Karl Popper Collection has acted acts as the institution responsible for translations and new editions of Popper’s work.
Note that the Karl Popper Collection and the Karl Popper Foundation are two independent institutions even though there are personal and thematic overlaps. The Collection is a part of the University Library — a research archive — and the Foundation is an organization, taking care of public activities in the spirit of Karl Popper writings and his philosophy of Critical Rationalism.
For more details, check out the website of the Karl Popper Collection.