Music theory is a field of study that describes the elements of music and includes the development and application of methods for composing and for analyzing music through both notation and, on occasion, musical sound itself. Broadly, theory may include any statement, belief, or conception of or about music (Boretz, 1995). A person who studies or practices music theory is a music theorist. Some music theorists attempt to explain the techniques composers use by establishing rules and patterns. Others model the experience of listening to or performing music. Though extremely diverse in their interests and commitments, many Western music theorists are united in their belief that the acts of composing, performing, and listening to music may be explicated to a high degree of detail (this, as opposed to a conception of musical expression as fundamentally ineffable except in musical sounds). Generally, works of music theory are both descriptive and prescriptive, attempting both to define practice and to influence later practice. Thus, music theory generally lags behind practice in important ways, but also points towards future exploration, composition, and performance. Musicians study music theory in order to be able to understand the structural relationships in the (nearly always notated) music, and composers study music theory in order to be able to understand how to produce effects and to structure their own works. Composers may study music theory in order to guide their precompositional and compositional decisions. Broadly speaking, music theory in the Western tradition focuses on harmony and counterpoint, and then uses these to explain large scale structure and the creation of melody.