In the writings on Croatian music of the 20th century, Aron Marko Rothmüller (1908-1993) is usually mentioned as a versatile and enterprising musician. His singing career of international importance stood out in particular. In contrast, his compositions began to be considered only recently: from the writings of the musicologist Eva Sedak, who emphasizes his role in the compositional reception of the Second Viennese School in Croatia, and Jascha Nemtsov, who suggests the context of the so-called New Jewish School as a framework for considering his work, to Tamara Jurkić Sviben, who discusses his role in both of these contexts. This thesis, which includes a catalogue of Rothmüller's works known to this day, is an attempt to systematically present his compositional work for the first time. By analyzing four selected pieces, as well as the composer's writings on music, the author tries to reconstruct the coordinates relevant for his compositional output. It seems that it was precisely these aspects, due to which Rothmüller's work has so far stood “on the edges” of the history of Croatian music, that have made it diverse and unique.