Ossip Gabrilowitsch (Осип Сoломонович Габрилович, Osip Solomonovich Gabrilovich; he used the German transliteration Gabrilowitsch in the West) (7 February [O.S. 26 January] 1878 – 14 September 1936) was a Russian-born American pianist, conductor and composer.
Ossip Gabrilowitsch was born in Saint Petersburg. He studied the piano and composition at the Saint Petersburg Conservatory, with Anton Rubinstein, Anatoly Lyadov, Alexander Glazunov and Nikolai Medtner among others. After graduating in 1894, he spent two years studying piano with Theodor Leschetizky in Vienna.
In July 1905 he recorded ten pieces for the Welte-Mignon reproducing piano, one of the first pianists to do so.
On 6 October 1909, he married Mark Twain's daughter Clara Clemens, a singer who appeared with him in recital. On 18 August 1910, their only child, Nina, was born at Mark Twain's home in Stormfield, Connecticut. Nina, the last known lineal descendant of Mark Twain, died on 16 January 1966 in a Los Angeles hotel. She had been a heavy drinker, and bottles of pills and alcohol were found in her room. Her death was ruled a suicide. 
From 1910 to 1914, he was conductor of the Munich Konzertverein (later known as the Munich Philharmonic). At the oubreak of World War I, he was put in jail following a pogrom. Through the intervention of the nuncio to Bavaria, Archbishop Eugenio Pacelli (later Pope Pius XII), Gabrilowitsch was freed from jail, and then he headed to the United States via Zürich in August 1914.
He settled in the US, and was offered the post of conductor of the Boston Symphony Orchestra. In declining, he recommended that the Boston board appoint the recently arrived Sergei Rachmaninoff. In 1918 he was appointed the founding director of the Detroit Symphony Orchestra, while still maintaining his life as a concert pianist. Before accepting the conductor's position, he demanded a new auditorium be built, and this was the impetus for the building of Orchestra Hall.
Gabrilowitsch composed a few works, primarily short piano pieces for his own use. He was a National Patron of Delta Omicron, an international professional music fraternity. He died from stomach cancer in Detroit in 1936 and, along with his daughter, Clara and her famous father, is buried in the Langdon plot of the Woodlawn Cemetery in Elmira, New York.
- 5 Klavierstücke, Op. 1
- No. 3 Valse lente (c. 1897)
- Gavotte in D minor, Op. 2
- Compositions for the piano, Op. 3
- No. 1 Caprice Burlesque (ca 1901)
- No. 2 Mazurka Mélancolique
- Thème varié pour piano, Op. 4
- Mélodie, Op. 8, No.1
- La Czarina, Mazurka Russe (The Tsarina, Russian Mazurka)
- Three Songs, Op. 11:
- Two Piano Pieces, Op. 12
- No. 1 Elegy
- No. 2 Etude for the left hand
- Near to thee ... [Song] Poem by Johann Wolfgang von Goethe, English version by Clara Clemens (ca. 1924)
- Clara Clemens: My husband Gabrilowitsch. Reprint of the ed. published by Harper, New York. New York, NY: Da Capo Press, 1979. ISBN 0-306-79563-9
- Cooke, James Francis: Great Pianists on Piano Playing: Godowsky, Hofmann, Lhévinne, Paderewski and 24 Other Legendary Performers. New York (Dover) 1999. (Reprint of the original edition 1917).
- Ossip Gabrilowitsch: Essentials of Touch. In James Francis Cook: Great pianists on piano playing: study talks with foremost virtuosos. Publisher: Theo. Presser & Co., Philadelphia 1917, page 122
- "Gabrilowitsch, Ossip", Encyclopædia Britannica (Encyclopædia Britannica Online Library Edition), 2008, retrieved 2008-04-28
- "Daughter Born to Mrs. Gabrilowitsch", The New York Times (Redding, Conn.), August 20, 1910: 7, ISSN 0362-4331, retrieved 2008-04-22
- Mark Twain Online
- Rabbi David G. Dalin. The Myth of Hitler's Pope. (Washington: Regency Publishing Inc., 2005) p. 50
- "Mark Twain's Daughter Safe". The Sun (New York, NY). 16 August 1914. Retrieved 6 February 2015.
- Delta Omicron National Patrons and Patronesses
- Mark Twain Online - Clara Clemens
- Ossip Gabrilowitsch plays for Welte-Mignon on 4 July 1905 Johannes Brahms Intermezzo in C major, Op. 119, No. 3 listen (help·info)