The Nikolay Karlovich Medtner Papers contain letters, programs, clippings, photographs, scores, books, realia, and other items related to Medtner's family life and career as a concert pianist. These materials date from 1826-1954, with the majority dating from 1914-1954. The Correspondence series takes up nearly half the collection and consists of family and general correspondence written between 1914 and 1954, containing over 1,900 letters in Russian, German, English, and French. Family correspondence (1914-1936) consists of approximately 500 letters by Nikolay and/or wife Anna to Ėmiliĭ Karlovich Metner with over 400 letters in reply. The general correspondence (1921-1954) contains significant letters and transcripts to and from Sergei and Nataliia Rachmaninoff, Leon and Olga Conus, Sofiia Aleksandrovna Satina, Konstantin Klimov, Madeleine Laliberté (Mrs. Albert Laliberté), Bernard and Cecile Pinsonneault, Abbé J.G. Turcotte, and smaller holdings of letters by other musicians and admirers. This series also contains condolence letters sent to Anna upon Nikolay’s death and a large quantity of unidentified letters.

The Programs series largely documents concerts given by Medtner in the U.S., Canada, Europe, and Russia between 1907 and 1946. There are also programs featuring Medtner’s works, presumably collected by the family. The Articles series (1910-1952) consists chiefly of newspaper clippings (often collected in scrapbooks, transcribed, and occasionally translated) and several longer articles written about Medtner. In addition, there is a brief article written by Medtner on the topic of musical inspiration. Aside from one photograph of Medtner himself, the Photography series is confined mostly to inscribed photographs of various musicians presented to Medtner, including two by Rachmaninoff.

The Miscellany series includes analytical notes, advertisements, and reviews pertaining to the Medtner Society's recordings; catalogues from Ėmiliĭ's publishing house Musaget' dating from 1912-1913; a 1927 address (with English translation) signed by 111 Moscow musicians and given to Medtner upon his visit to Russia; a diploma (1928) from the Royal Academy of Music; and a humorous scroll dated 1936. A bronze bust of Medtner executed by Karen Vogel and a posthumous plaster cast of Medtner's hands are included in this collection. Among the books are poetic works by Pushkin and Tiutchev, with Medtner's annotations, Medtner's personal copy of Muza i moda , and a copy of Ėmiliĭ's Modernizm’ i Muzika .

The Music series consists of printed scores and three manuscripts in Medtner's hand: Russian Round Dance, op. 58, no. 1 ; a 1896 work entitled Prelude, piano, E♭ minor , dedicated to Anna (possibly reworked as Op. 14/1); and an early vocal piece entitled Romance , also dedicated to Anna (possibly reworked as Op. 3/1). Among the printed music holdings is a bound volume containing musical settings to Pushkin's texts by various composers compiled by V.A. Kiselev as well as a printed score to Arthur Lourié’s Formes en l’air , with a written dedication to Medtner initialed by Rachmaninoff.

A few explanatory words regarding transliteration of the composer's surname: although the correct transliteration of the Russian-born composer's surname would be more precisely rendered according to the Library of Congress's transliteration system as "Metner," the composer himself favored the Germanic spelling of his name, "Medtner," in Roman script; the latter form, through which the composer gained renown in the West, has therefore been retained within this document. Conversely, the Library of Congress transliteration system has been adhered to in transliterating the name of the composer's brother, Ėmiliĭ Metner (who neither cultivated a career in the West, nor adopted the Germanic spelling of his surname). Alternate spellings for Russian names and titles that appear in this finding aid--including those defined by convention as well as standardized transliteration--have been included in an appendix to facilitate searching. A modified Library of Congress transliteration system, excluding ligatures and accent marks, has been adopted in this finding aid.