Organized in two series: Series 1, Original and Published Music, 1871-1902 and Series 2, Personal Papers, 1888-1913. Series 1 is arranged alphabetically by title and Series 2 is unarranged.
Otto Friedrich Mesloh was born in New Bremen, Ohio on February 26, 1867 to John Henry and Wilhelmina (Boesel) Mesloh. Although a machinist by trade, according to Karl R. Mesloh, "his love of music won out and Otto became a professional musician." His mother and two sisters, Emma and Dora Mesloh, were all pianists. As a young musician Otto played both cornet, flute, piccolo, and saxophone with The Big Six Band of Springfield, Ohio, and traveled with the Waite Comedy Company and the Bubb and Bennett and Waite's Western Company ensembles. He performed as a cornetist with the John Philip Sousa Band between September 7 and December 4, 1898. He also played as the band's cornet soloist durng the ensemble's Manhattan Beach concerts between June 17 and September 4, 1899. Other military bands that Mesloh performed with included the 69th Regimental Band, Callahan's New York Marine Band, the British Bards Band, and Somerset's Military Band.
After departing the Sousa Band in 1899, Mesloh joined the Elite Musicial Four, considered at that time to be one of of the greatest musical vaudeville teams which performed a variety of popular music selections on cornets, flugelphones, saxophones, and xylophones. The quartet was involved in a serious train derailment on June 11, 1906 when it was returning to New York City from a performance in Atlantic City. The ensemble's manager, George Van Duzen, was killed and Mesloh was badly injured. Mesloh was eventually able to continue his career as a performer and teacher in 1908, the injuries that he sufferred from this train accident impacted his work as a musician for the rest of his life.