In the field of recorded music, a hidden track (sometimes called a secret track or ghost track) is a piece of music that has been placed on a CD, audio cassette, vinyl record or other recorded medium in such a way as to avoid detection by the casual listener. In some cases, the piece of music may simply have been left off the track listing, while in other cases more elaborate methods are used. In some rare cases a "hidden track" is actually the result of an error that occurred during the mastering stage of the record's production.

A vinyl record may be double-grooved, with the second groove containing the hidden tracks. Notable examples of double-grooving are Monty Python's infamous "three-sided" Matching Tie and Handkerchief, Tool's Opiate EP and Mr. Bungle's Disco Volante.

On indexed media such as compact discs, double-grooving cannot be used, but there are additional methods of hiding tracks, such as:

Often it is unclear whether a piece of music should be considered a hidden track. For example, "Her Majesty", which is preceded by fourteen seconds of silence, was originally unlisted on The Beatles' Abbey Road but is listed on current versions of the album. This is allegedly the first instance of a hidden track (except that The Beatles has a hidden track after "Cry Baby Cry", referred to only as "Can You Take Me Back", see "Cry Baby Cry" for more). The song snippet at the end of Sgt. Pepper's Lonely Hearts Club Band is considered by some to be a hidden track, by others to be noise not worthy of such a designation, and by others to be part of "A Day in the Life."

Felipe Andres Coronel (born February 19, 1978), better known by the stage name Immortal Technique, is an American rapper of Afro-Peruvian descent as well as an urban activist. He was born in Lima, Peru and raised in Harlem, New York. Most of his lyrics focus on controversial issues in global politics. The views expressed in his lyrics are largely commentary on issues such as class struggle, poverty, religion, government and institutional racism.

Immortal Technique has voiced a desire to retain control over his production, and has stated in his music that record companies, not artists themselves, profit the most from mass production and marketing of music. He claimed in an interview to have sold close to 200,000 copies of his three official releases.

Coronel is African-Peruvian and was born in 1978 in a military hospital in Lima. His family emigrated in 1980 to Harlem. During his teenage years he was arrested multiple times due in part to what he has said was "selfish and childish" behavior. He attended Hunter College High School on the Upper East Side of Manhattan. Shortly after enrolling in Pennsylvania State University, he was arrested and charged with assault-related offenses due to his involvement in an altercation between fellow students, the charges stemming from this incident led to him being incarcerated for a year. After being paroled, he took political science classes at Baruch College in New York City for two semesters at the behest of his father, who allowed Coronel to live with him on the condition that he go to school. Honing his rapping skills in jail, and unable to find decent wage-paying employment after his release, Coronel began selling his music on the streets of New York while battling with MCs whenever the opportunity arose. This, coupled with his victories in numerous freestyle rap competitions of the New York underground hip hop scene such as Rocksteady Anniversary, Braggin Rites and others, led to his reputation as a ferocious Battle MC.

Jason Mraz ( /məˈræz/; born June 23, 1977 in Mechanicsville, Virginia) is an American singer-songwriter. Mraz released his debut album, Waiting for My Rocket to Come, which contained the hit single "The Remedy (I Won't Worry)", in 2002, but it was not until the release of his second album, Mr. A-Z, in 2005, that Mraz achieved major commercial success. The album peaked at number five on the Billboard 200 and sold over 100,000 copies in the US. In 2008, Mraz released his third studio album, We Sing. We Dance. We Steal Things. The album debuted at number three on the Billboard 200 and was a commercial success worldwide, peaking in the top ten of many international charts.

Mraz's international breakthrough came with the release of the single "I'm Yours" from the album We Sing. We Dance. We Steal Things. The single peaked at number six on the Billboard Hot 100, giving Mraz his first top ten single. The song was on the Hot 100 for 76 weeks, beating the previous record of 69 weeks held by LeAnn Rimes' "How Do I Live". The song was a huge commercial success in the US, receiving a 5x platinum certification from the RIAA for sales of over five million. The song was successful internationally, topping the charts in New Zealand and Norway and peaking in the top ten of multiple international charts.

Justin Randall Timberlake (born January 31, 1981) is an American singer, actor, and businessman. He achieved early fame when he appeared as a contestant on Star Search, and went on to star in the Disney Channel television series The New Mickey Mouse Club, where he met future bandmate JC Chasez. Timberlake became famous in the late 1990s as the lead singer and youngest member of the boy band 'N Sync, whose launch was financed by Lou Pearlman.

In 2002, he released his debut solo album, Justified, which sold more than seven million copies worldwide. The album was a commercial success, spawning the hits "Cry Me a River" and "Rock Your Body". Timberlake continued his success with his second solo album, FutureSex/LoveSounds (2006), debuting at number one on the Billboard 200 chart, and produced the US number-one hit singles "SexyBack", "My Love", and "What Goes Around... Comes Around".

Timberlake has won six Grammy Awards and four Emmy Awards. His first two albums made him one of the most commercially successful singers in the world, each selling in excess of 7 million copies. He also has an acting career, having starred in films such as The Social Network, Bad Teacher and Friends with Benefits. His other ventures include record label Tennman Records, fashion label William Rast, and the restaurants Destino and Southern Hospitality.

Alanis Nadine Morissette (born June 1, 1974) is a Canadian singer-songwriter, guitarist, record producer, and actress. She has won 16 Juno Awards and seven Grammy Awards, was nominated for two Golden Globe Awards and also shortlisted for an Academy Award nomination. Morissette began her career in Canada, and as a teenager recorded two dance-pop albums, Alanis and Now Is the Time, under MCA Records Canada.

Her first international album was the rock-influenced Jagged Little Pill, released in 1995. Jagged has sold more than 33 million units globally. Her following album, Supposed Former Infatuation Junkie, was released in 1998 and was a success as well. Morissette took up producing duties for her subsequent albums, which include Under Rug Swept, So-Called Chaos and Flavors of Entanglement. Morissette has sold more than 60 million albums worldwide. Morissette is also known for her powerful and emotive mezzo-soprano voice.

Morissette acquired United States citizenship in 2005.

Morissette was born June 1, 1974 in Ottawa, Ontario, Canada, the daughter of Georgia Mary Ann (née Feuerstein), a teacher of Hungarian descent, and Alan Richard Morissette, a French-Canadian high school principal. She has a twin brother, Wade Morissette, (also a musician) who was born 12 minutes after her. Morissette was raised Catholic. She attended Glebe Collegiate Institute (Ottawa, Canada) for high school.