Micrologus is a medieval music treatise written by Hucbald, a Benedictine monk, around the 10th century. It focuses on the theory of music, particularly the practice of melody and harmony. The work is significant for its early exploration of musical notation and the principles of counterpoint, which would later influence the development of Western music. The treatise is divided into several sections, discussing topics such as scales, intervals, and the relationship between music and mathematics. Micrologus serves as an important historical document, providing insight into the musical practices and theories of the medieval period.