Jam bands are musical groups whose albums and live performances relate to a fan culture that originated with the 1960s group Grateful Dead and continued in the 1990s and beyond. The performances of these bands often feature extended musical improvisation ("jams") over rhythmic grooves and chord patterns and long sets of music that cross genre boundaries.^[2]

While the seminal group Grateful Dead were originally categorized as psychedelic rock,^[3] by the 1990s the term "jam band" was used for groups playing a variety of genres, including those outside of rock such as funk, progressive bluegrass, and jazz fusion. The term is also used for some groups playing blues, country music, folk music, world music, and electronic music.^[2]

Taping

Jam bands often allow their fans to make tapes or recordings of their live shows, a practice which many other musical genres call "illegal bootlegging". The Grateful Dead encouraged this practice, which helped to create a thriving scene around the collecting and trading of recordings of Grateful Dead live performances. Most of the live shows on the Grateful Dead's 30 years of touring were recorded. It was probably the trading of recordings of Grateful Dead shows which built the band's fan base. Starting in 1984,^[22] the band recognized the fact that people were already "unofficially" taping their shows, so they started to sell taper tickets for a taper's section which allowed the tapers to bring their own microphones and tape decks to record with, as well as wrangle the tapers into one area of the venue so to keep them from interfering with other concertgoers. This type of encouragement has spread to nearly all of the jam bands. Some jam band enthusiasts argue that if a band does not allow fans to tape their live shows, this band is not actually a jam band in the Grateful Dead tradition.

Fans trade recordings and collect recordings of different live shows because improvisational jam bands play their songs differently at each performance and generally mix up their set lists so as to encourage fans to see them on multiple nights. Fans collect various versions of their favorite songs and actively debate which is the "best version" of any particular song, keeping lists of notable versions of those songs. They keep track of how many times a specific song has been played and note the frequency of performances of certain songs, and note the relative rarity or commonality of its performance during certain years. This increases the momentousness of a rare song being dusted off and played live, or played for the first time.^[23] Some bands play with this phenomenon by throwing short little "teases" into their sets. Playing, for example, a few bars of a famous cover song or hinting at a popular jam and then either never getting around to playing the song, or coming back to it after an extended jam. The use of segues to blend strings of songs together is another mark of a jam band, and one which makes for treasured tapes.^[24]