In 1839 Friedrich August Kummer (1797–1879) wrote Violoncelloschule für den ersten Unterricht (Violoncello School for Preliminary Instruction), Op. 60. The method has remained a staple of teaching literature ever since. As an appendix to this work, Kummer composed several duets of increasing difficulty that can be paired with the topics and exercises learned in the lessons. As cello technique changed during the nineteenth century, several cellists (Friedrich Dotzauer, Bernhard Romberg, and Leo S...