Ultra was the designation adopted by British military intelligence in June 1941 for wartime signals intelligence obtained by breaking high-level encrypted enemy radio and teleprinter communications at the Government Code and Cypher School at Bletchley Park.Ultra eventually became the standard designation among the western Allies for all such intelligence. The name arose because the intelligence thus obtained was considered more important than that designated by the highest British security classification then used (Most Secret) and so was regarded as being Ultra secret. Several other cryptonyms had been used for such intelligence. British intelligence first designated it "Boniface"—presumably to imply that it was the result of human intelligence. The U.S. used the codename "Magic" for its decrypts from Japanese sources.

Much of the German cipher traffic was encrypted on the Enigma machine. Used properly, the German military Enigma would have been virtually unbreakable; in practice, shortcomings in operation allowed it to be broken. The term "Ultra" has often been used almost synonymously with "Enigma decrypts". However, Ultra also encompassed decrypts of the German Lorenz SZ 40/42 machines that were used by the German High Command, and the Hagelin machine and other Italian and Japanese ciphers and codes such as PURPLE and JN-25.

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."

Pierre David Guetta (7 November 1967), known professionally as David Guetta (French pronunciation: [daˌvid ɡɛˈta]), is a French house music producer and DJ. Originally a DJ at nightclubs during the 1980s and 1990s, he co-founded Gum Productions and released his first album, Just a Little More Love, in 2002. Later, he released Guetta Blaster (2004) and Pop Life (2007). His 2009 album One Love included the hit singles "When Love Takes Over" (featuring Kelly Rowland), "Gettin' Over You" (featuring Chris Willis, Fergie & LMFAO) and "Sexy Bitch" (featuring Akon), the last becoming a top five hit in the United States and all three reaching #1 in the United Kingdom, as well as another internationally known single called "Memories" featuring Kid Cudi which became a top five hit in many countries. Guetta has sold over three million albums and 15 million singles worldwide. He is currently one of the most sought-after music producers. As at 2012 David Guetta is the world's most popular DJ, claiming the #1 poll position of the DJ Mag 100 popularity poll.