Organology (from Greek: ὄργανον – organon, "instrument" and λόγος – logos, "study") is the science of musical instruments and their classification. It embraces study of instruments' history, instruments used in different cultures, technical aspects of how instruments produce sound, and musical instrument classification. There is a degree of overlap between organology, ethnomusicology (being subsets of musicology) and the branch of the acoustics devoted to musical instruments.
A number of ancient cultures left documents detailing the musical instruments used and their role in society; these documents sometimes included a classification system. The first major documents on the subjects from the west, however, date from the 16th century, with works such as Sebastian Virdung's Musica getuscht und ausgezogen (1511), and Martin Agricola's Musica instrumentalis deudsch (1529).
One of the most important organologists of the 17th century is Michael Praetorius. His Syntagma musicum (1618) is one of the most quoted works from that time on the subject, and is the source of much of what we know about renaissance musical instruments. Praetorius's Theatrum instrumentorium (1620) contains possibly the first pictures of African instruments in a European publication.
For much of the 18th and 19th centuries, little work was done on organology. Explorers returned to Europe with instruments from different cultures, however, so that by the end of the 19th century, some musical instrument collections were quite large. This led to a renewed interest in the subject.
One of the most important organologists of the 20th century was Curt Sachs, who, as well as writing Real-Lexicon der Musikinstrumente (1913) and The History of Musical Instruments (1942), devised with Erich von Hornbostel the Hornbostel-Sachs scheme of instrument classification, published in 1914 (Hornbostel–Sachs). This remains the most common classification scheme used by organologists today, despite some criticism. Andre Schaeffner introduced a system based on state-of-matter of the sound-producing mechanism, giving rise to two top-level categories: solid (containing strings and percussion), and gas (containing woodwind and brass). With the invention of hydraulophone, the physics-based organology has been expanded to use solid, liquid, and gas, wherein the top-level category is the state-of-matter of the material that makes the sound. Reference to Kartomi's book, page 173.
A number of societies exist dedicated to the study of musical instruments. Among the more prominent are the Galpin Society, based in the United Kingdom; and the American Musical Instrument Society, based in the United States.