The Viennese euthanasia clinic Am Spiegelgrund scrupulously listed all deaths from the clinic's foundation in July 1940 to the end of the war. Although the euthanasia killings were systematically disguised by means of incomplete entries, the Book of the Dead represents an invaluable source which made possible the reconstruction of the names of 789 Spiegelgrund victims, with the dates of their birth, committal to the clinic, and death.
Since 2002, the book is preserved in the Viennese City and State Archive (WStLA).