Although the scope of the collection officially begins with the Balkan wars in 1912, it does include some background materials for earlier periods. Foreign diplomatic documentation of the pre-1912 period is well represented at the Hoover Institution.
The holdings for the Balkan wars and World War I, 1912–18, constitute a strong research collection, and the events are documented by a variety of sources. The collection includes a large gathering of materials relating to Bulgaria at the Paris Peace Conference. Other topics well documented within the collection are the Balkan conferences and the Balkan pact, the September 1923 uprising, the Zveno organization, the Bulgarian involvement in World War II, and Communist Party activities.
The postwar period is the most strongly represented period in the collection, including an extensive collection of leading governmental and administrative sources and documentary collections of the Communist Party, the official ruling party since the end of 1946.
Important archival collections include the papers of Georgi M. Dimitrov, Ferdinand I (czar of Bulgaria, 1861-1948), Dora Gabensky, Racho Petrov, and Dimitri Stanchov, as well as the more recently acquired documentation of Kyril Drenikoff, politician and émigré collector. A large collection of ephemeral publications documenting the political process during the years since 1990 is included in the Bulgarian subject collection.