Today the term guitar solo is commonly taken to refer specifically to the rock music genre. Although solo passages for guitar are found in many musical genres, the 'guitar solo' has become a characteristic part of rock music. Guitar solos are usually performed with electric guitar with the timbral effect known as distortion. Rock bands sometimes have two guitarists, designated 'lead' and 'rhythm', the 'lead' player taking the solos while the 'rhythm' player accompanies. Lonnie Johnson was one of the first, if not the first, musicians (in modern music especially) to play single string guitar solos.
Most examples of rock music are based around songs in very traditional forms. The main formal features are therefore verses, choruses, and bridges. The guitar solo is usually the most significant instrumental (that is, non-vocal) section of a mainstream rock song. In other rock-related genres such as pop and dance music, the keyboard synthesizer usually plays this melodic role.
This use of an instrumental interlude to a song is influenced by blues musicians like John Lee Hooker and Muddy Waters, who were influential in the development of rhythm and blues (e.g., Bo Diddley), rock and roll (e.g. Chuck Berry) and hence more modern forms of rock music. In most cases, the rock guitar solo is a short instrumental section of the song. In the classic verse-chorus form it quite often falls between the second chorus and third verse. As well, extended guitar solos are sometimes used at the end of songs, such as Guns N' Roses's November Rain, Pink Floyd's Comfortably Numb, Lynyrd Skynyrd's Free Bird ,Van Halen's Eruption and Led Zeppelin's Stairway To Heaven.
The use of the guitar solo in heavy metal music was especially notable during the 1980s, where guitar solos were common, and a lead guitarist of a band might be as well-known as the singer. During this time the use of techniques such as harmonics became more widely used. Later, guitarists who had developed considerable technical facility began to release albums which consisted only of guitar compositions.
Guitar solos in popular music went out of fashion in the mid 1990s, coinciding with the rise in popularity of Nu metal which did not feature guitar solos prominently. Following nu metal, the guitar solo in pop and popular rock music also declined in popularity. In recent years it has come back into fashion in heavy metal music with many bands showcasing solos in many of their compositions. Guitar solos remain important in rock, heavy metal, blues, and jazz music
