The collection includes correspondence, manuscripts, memoirs, diaries, notes, subject files, documents, photographs, and printed materials. Most of the material in the collection concerns Nikolaev's tenure as military attachʹe at the Russian embassy in Washington. Cataloged correspondents include Mikhail T. Florinsky and Geroid T. Robinson. There is a typescript by Vasiliĭ O. Kli︠u︡chevskiĭ, "Kratkoe posobie po russkoĭ istorii." Among the correspondence are cablegrams and official communications to the Russian embassy during World War I and the revolutionary period. Manuscripts, mostly by Nikolaev, concern contemporary and historical military topics. Diaries and memoirs deal with Nikolaev's travels to Europe during World War I and his activities as military attachʹe. Among orders granted to Nikolaev is the "Order of the Sacred Treasure," signed and sealed by the Japanese Emperor Meiji (1911). Printed materials include many articles by Nikolaev.

Papers include typed carbons of correspondence, memoirs, speeches, and biographical materials. The correspondence consists of letters to and from Crane, 1869-1939, and telegrams and letters to his wife upon his death. The memoirs include information on his diplomatic service and travels. The speeches, 1910-1930, are largely based on his travels and activities. There are diaries by other persons of his trips to Albania, Russia in 1921, and to the Near East. Finally, biographical materials include editorials, articles, and speeches. While a sizable amount of material concerns Russia, the collection includes information on his other activities as well.

Two typescript memoirs: "Voennoinzhenernaiia komissiia russkogo pravitel'stva v Severo-Amerikanskikh Soedinennykh Shtatakh v Pervuiu mirovuiu voinu 1914-1917 g."; and "Iz Niu Iorka v Rossiiu i iz Sovetskoi Rossii v Niu Iork. Moe prebyvanie v Sovetskoi Rossii v 1917-1919 g. i ukhod iz nee" (combined ca. 50 p.). There are also two curricula vitae for Baldin, an offprint of an article on engineering and a typescript of an article on enginering by him.