Despite their significance, the writings on Japanese music by Prussian medical scientist and physician Leopold Muller, published in Yokohama in a series from 1874 to 1876, have been nearly forgotten and marginalized even in historical research on the courtly gagaku traditions they focus upon. This study with full translation into both English and Japanese illuminates and reassesses Muller's pioneering contribution. It situates the essay-series historically in the light of an important line of thought about the evolution of ancient gagaku that arose only in the mid-twentieth century, as well...