Guido Adler (1855–1941) was an influential Austrian musicologist and composer, primarily associated with the field of music theory and historical musicology. Though not primarily known as a performing artist, Adler's contributions to music were significant in shaping musicology as a discipline. He is best recognized for his work in the late 19th and early 20th centuries, particularly through his foundational text, "Grundzüge der Musikgeschichte" (Principles of Music History), published in 1885. This work laid the groundwork for systematic musicological study. Adler's genre focus encompassed classical music, with a particular emphasis on the historical development of Western art music. He was instrumental in establishing the Vienna School of musicology, promoting a scientific approach to music research that influenced generations of scholars. His emphasis on the importance of historical context in understanding music has had a lasting impact on musicological methodologies. Additionally, Adler contributed to the establishment of several musicological societies and journals, further solidifying his role in the professionalization of musicology. His legacy continues to resonate in the field, as his principles and methods are still foundational in music studies today.