Robert Lachmann’s letters to Henry George Farmer, from the years 1923-38, provide insightful glimpses into his life and his progressive research projects. From an historical perspective, they offer critical data concerning the development of comparative musicology as it evolved in Germany during the early decades of the twentieth century. The fact that Lachmann sought contact with Farmer can be explained from their mutual, yet diverse interests in Arab music, particularly as they were then considered to be the foremost European scholars in the field. During the 1932 Cairo International Congress on Arab Music, they were selected as presidents of their respective committees.