Music theory is the study of the practices and possibilities of music. The Oxford Companion to Music describes three interrelated uses of the term "music theory": The first is what is otherwise called "rudiments" taught as the elements of notation, of key signatures, of time signatures, of rhythmic notation, so on; the second is the study of writings about music from ancient times onwards. The third is an area of current musicological study that seeks to define processes and general principles in music—a sphere of research that can be distinguished from analysis in that it takes as its starting-point not the individual work or performance but the fundamental materials from which it is built. Music theory is concerned with describing how musicians and composers make music, including tuning systems and composition methods among other topics; because of the ever-expanding conception of what constitutes music, a more inclusive definition could be that music theory is the consideration of any sonic phenomena, including silence, as they relate to music.

This is not an absolute guideline. However, this medieval discipline became the basis for tuning systems in centuries, it is included in modern scholarship on the history of music theory. Music theory as a practical discipline encompasses the methods and concepts composers and other musicians use in creating music; the development and transmission of music theory in this sense may be found in oral and written music-making traditions, musical instruments, other artifacts. For example, ancient instruments from Mesopotamia and prehistoric sites around the world reveal details about the music they produced and something of the musical theory that might have been used by their makers. In ancient and living cultures around the world, the deep and long roots of music theory are visible in instruments, oral traditions, current music making. Many cultures, at least as far back as ancient Mesopotamia and ancient China, have considered music theory in more formal ways such as written treatises and music notation.

Practical and scholarly traditions overlap, as many practical treatises about music place themselves within a tradition of other treatises, which are cited just as scholarly writing cites earlier research. In modern academia, music theory is a subfield of musicology, the wider study of musical cultures and history. Etymologically, music theory is an act of contemplation of music, from the Greek θεωρία, a looking at, contemplation, theory a sight, a spectacle; as such, it is concerned with abstract musical aspects such as tuning and tonal systems, scales and dissonance, rhythmic relationships, but there is a body of theory concerning practical aspects, such as the creation or the performance of music, ornamentation and electronic sound production. A person who researches, teaches, or writes articles about music theory is a music theorist. University study to the MA or PhD level, is required to teach as a tenure-track music theorist in a US or Canadian university. Methods of analysis include mathematics, graphic analysis, analysis enabled by Western music notation.

Comparative, descriptive and other methods are used. Music theory textbooks in the United States of America include elements of musical acoustics, considerations of musical notation, techniques of tonal composition, among other topics. Preserved prehistoric instruments and depictions of performance in artworks can give clues to the structure of pitch systems in prehistoric cultures. See for instance Paleolithic flutes, Gǔdí, Anasazi flute. Several surviving Sumerian and Akkadian clay tablets include musical information of a theoretical nature lists of intervals and tunings; the scholar Sam Mirelman reports that the earliest of these texts dates from before 1500 BCE, a millennium earlier than surviving evidence from any other culture of comparable musical thought. Further, "All the Mesopotamian texts are united by the use of a terminology for music that, according to the approximate dating of the texts, was in use for over 1,000 years." Much of Chinese music history and theory remains unclear.

The earliest texts about Chinese music theory are inscribed on the stone and bronze bells excavated in 1978 from the tomb of Marquis Yi of the Zeng state. They include more than 2800 words describing practices of music pitches of the time; the bells produce two intertwined pentatonic scales three tones apart with additional pitches completing the chromatic scale. Chinese theory starts from numbers, the main musical numbers being twelve and eight. Twelve refers to the number of pitches; the Lüshi chunqiu from about 239 BCE recalls the legend of Ling Lun. On order of the Yellow Emperor, Ling Lun collected twelve bamboo lengths with thick and nodes. Blowing on one of these like a pipe, he found its sound agreeable and named it huangzhong, the "Yellow Bell." He heard phoenixes singing. The male and female phoenix each sang six tones. Ling Lun cut his bamboo pipes to match the pitches of the phoenixes, producing twelve pitch pipes in two sets: six from the male phoenix and six from the female: these were called the lülü or the shierlü.

The lülü formed the ritual scale to which many

I Won't Go for More is a song by Belgian recording artist Selah Sue. It was written by Sue and Birsen Uçar and produced by Robin Hannibal for her second studio album Reason, featuring co-production from Itai Shapira and Salva. Distributed by Warner Music Group, it was released as the album's third single by Because Music on June 15, 2015. Credits adapted from the Reason liner notes. Andrew Dawson – mixing Robin Hannibal – producer, instruments Mike Malchicoff – mixing assistance Jake Najor – drums Sam Robles – baritone saxophone Paul Salva – drums, percussion, co-production Itai Shapira – bass, guitar, co-production Todd Simon – flugelhorn, trumpet Sanne Putseys – composer Birsen Uçar – lyrics Tracy Wannomae – alto saxophone, bass clarinet, tenor saxophone SelahSue.com – official website

Saad Tedjar is an Algerian footballer, playing for ASO Chlef in the Algerian Ligue Professionnelle 1. In 2006, Tedjar signed a five-year contract with Paradou AC. In June 2009, Tedjar was loaned out by his club to JS Kabylie for one season with a buy option at the end of the loan period, on condition that Paradou AC do not gain promotion. In his first season with the club, Tedjar scored 3 goals in 23 games as JSK finished third in the league. On June 4, 2010, JS Kabylie took up the buy option on Tedjar, the player signed a two-year contract with the club. On August 29, 2010, he scored a goal against Egypt's Al Ahly in the 2010 CAF Champions League group stage, helping his side become the first team to earn a semi-final spot after drawing 1-1. On April 18, 2010, Tedjar made his debut for the Algeria A' national team as a substitute in an African Championship of Nations qualifier against Libya. On August 12, 2011, Tedjar was called up for the first time to the Algerian National Team by Vahid Halilhodžić for a 2012 Africa Cup Nations qualifier against Tanzania.

Won the Algerian Cup twice with JS Kabylie in 2011 and USM Alger in 2013 Saad Tedjar at Soccerway Saad Tedjar at DZFoot.com