A mashup or bootleg (also mesh, mash up, mash-up, blend and bastard pop/rock) is a song or composition created by blending two or more pre-recorded songs, usually by overlaying the vocal track of one song seamlessly over the instrumental track of another. To the extent that such works are "transformative" of original content, they may find protection from copyright claims under the "fair use" doctrine of copyright law.

Mashups are known by a number of different names:

In addition, more traditional terms such as "edits" or (unauthorized) "remixes" are favored by many "bootleggers" (also known as 'leggers).^{[citation needed]}

The practice of assembling new songs from purloined elements of other tracks stretches back to the beginnings of recorded music. If one extends the definition beyond the realm of pop, precursors can be found in musique concrète, as well as the classical practice of (re-)arranging traditional folk material and the jazz tradition of reinterpreting standards. In addition, many elements of mashup culture have antecedents in hip hop and the DIY ethic of punk as well as overlap with the free culture movement.

Music is an art form whose medium is sound and silence. Its common elements are pitch (which governs melody and harmony), rhythm (and its associated concepts tempo, meter, and articulation), dynamics, and the sonic qualities of timbre and texture. The word derives from Greek μουσική (mousike; "art of the Muses").

The creation, performance, significance, and even the definition of music vary according to culture and social context. Music ranges from strictly organized compositions (and their recreation in performance), through improvisational music to aleatoric forms. Music can be divided into genres and subgenres, although the dividing lines and relationships between music genres are often subtle, sometimes open to individual interpretation, and occasionally controversial. Within "the arts", music may be classified as a performing art, a fine art, and auditory art. There is also a strong connection between music and mathematics.

To many people in many cultures, music is an important part of their way of life. Ancient Greek and Indian philosophers defined music as tones ordered horizontally as melodies and vertically as harmonies. Common sayings such as "the harmony of the spheres" and "it is music to my ears" point to the notion that music is often ordered and pleasant to listen to. However, 20th-century composer John Cage thought that any sound can be music, saying, for example, "There is no noise, only sound." Musicologist Jean-Jacques Nattiez summarizes the relativist, post-modern viewpoint: "The border between music and noise is always culturally defined—which implies that, even within a single society, this border does not always pass through the same place; in short, there is rarely a consensus ... By all accounts there is no single and intercultural universal concept defining what music might be."

Adam Richard Wiles (born 17 January 1984), better known by his stage name Calvin Harris, is a Scottish DJ, singer, songwriter, and record producer. His gold-selling debut album, I Created Disco, was released in 2007 and contained the top ten singles "Acceptable in the 80s" and "The Girls". His second studio album, Ready for the Weekend (2009), reached number one in the UK Album Chart and includes the chart-topper "I'm Not Alone", the UK top five hit "Ready for the Weekend", and the singles "Flashback" and "You Used to Hold Me".

A remix album titled L.E.D. Festival was released in July 2010 as a free album in the August issue of Mixmag. Harris is currently working on his third studio album—due for release in 2012—which has produced the singles "Awooga", "Bounce", "Feel So Close", and "Let's Go". He has written and produced records for other recording artists including Kylie Minogue, Sophie Ellis-Bextor, Dizzee Rascal, Rihanna (on the international chart topper "We Found Love"), and Kesha.