The collection consists of correspondence from such ballet and theater personalities as Sergeĭ Khudi︠a︡kov, Sergeĭ Lifar,́ Nadezhda Nikolaeva-Legat, Alekander Sanin and Vera Trefilova. There is also one letter each from Zinaida Gippi︠u︡s, Nadezhda Teffi, Boris Zaĭt︠s︡ev and Vladimir Zeeler. In addition, there are several typed manuscripts by Pleshcheev, including his book-length biography of E.N. Roschina-Insarova, and clippings of newspaper articles by Pleshcheev.

The collection includes correspondence from Konstantin Balḿont, Nikolaĭ Evreĭnov, Zinaida Gippius, Georgiĭ Grebenshchikov, Vasiliĭ Maklakov, Sergeĭ Potresov and Nadezhda Teffi. There is one letter each from Boris Bakhmeteff, Vera Bunina, Aleksandr Grechaninov, Aleksandr Kuprin and Alekseĭ Tolstoĭ. The manuscripts include poems and a play scenario by Nadezhda Teffi as well as Roshchina-Insarova's autobiographical essays and article about Sergeĭ Lifar.́ In addition, there are three scrapbooks containing clippings and programs of Roshchina-Insarova's performances, and approximately 40 photographs of her.