The Kestenberg Estate in The Archive of Israeli Music, founded by Dr. Herzl Shmueli, contains over 1100 manuscripts, articles, photographs and letters, including 700 pieces of correspondence with musicians, artists and other personalities from all over the world.
Shmueli, who succeeded Kestenberg as the director of the music teachers' education seminar Midrasha leMenchanchim leMusika in 1953, reserved for himself the right to work first on the collection. But Herzl Shmueli died at the age of eighty-one on March 21, 2001, without having tackled this project.
In 2004, Ann-Kathrin Seidel catalogued and consecutively numbered the items in the Kestenberg estate, which had previously been put in a preliminary order. The new order forms the basis for both the Findbuch (catalogue) Seidel created at the request of the Berlin University of the Arts and the Leo Kestenberg Databank she compiled.
The estate documents are to some extent in critical condition. With the exception of the letters, all materials were filed on top of each other in cardboard folders. In most cases, the papers were bent or torn. Additionally, all documents with multiple pages were held together by paper clips, frequently rusty, so that the rust already had eaten well into the paper. The document storage was improved in 2004, when the rusty paper clips were removed and the documents were put into individual protective sleeves.