Anthrax is an American heavy metal band from New York City, NY, formed in 1981. Founded by guitarists Scott Ian and Danny Lilker, the band has since released ten studio albums and 20 singles, and an EP featuring Public Enemy. The band was one of the most popular of the 1980s thrash metal scene. When thrash metal began to gain a major following in the mid-to-late 1980s, Anthrax were dubbed one of the "big four" of thrash metal alongside Metallica, Megadeth and Slayer. They were also one of the early thrash metal bands to sign to a major label (Island Records, in 1985).

The band line-up has been changed numerous times; following the departure of drummer Dave Weiss and bassist Kenny Kushner, several musicians replaced both band members' roles, though Paul Kahn and Greg Walls were the first to do so. In addition to this aspect, there were multiple vocalists involved in Anthrax, with Neil Turbin, Joey Belladonna and John Bush being among the frontmen of the band. Scott Ian, however, has been in the band since its formation. Ian and Charlie Benante, who joined Anthrax in 1983, are the only constant members that appear on every album. Bassist Frank Bello has played on every album with exception of the band's debut. Classic singer Joey Belladonna has returned to the band and appears on Worship Music which is his first studio album with the band since 1990's Persistence of Time.

Defiance was a thrash metal band from Oakland, California. While virtually unknown to mainstream metal and rock circles, Defiance is known as one of the classic second-tier thrash bands to come from the Bay Area thrash metal scene.^{[citation needed]} They played a decidedly technical style of thrash originally evoking bands like Testament, though they would later move on to playing in their own unique, more progressive thrash style. They reformed in 2005 and have since release an album entitled The Prophecy in late 2009.

Defiance was formed in 1985 by guitarist Brad Bowers, drummer Matt Vander Ende, and bassist Mike Kaufmann. Doug Harrington joined later but left the band not long after due to conflicts with Bowers, and was replaced by Jim Adams. Eventually the band ousted Bowers and replaced him with Harrington. In 1987 the band recruited a vocalist in Mitch Mayes.

Now with a stable and complete lineup, Defiance began playing shows in the Bay Area. With the local thrash scene gaining momentum, the band attained local notoriety. Their first demo was released in 1987. Shortly afterwards Mayes left the band and was replaced by Ken Elkington. With Elkington the band issued their Hypothermia demo in 1988. This demo caught the attention of the independent metal label Roadracer Records, who signed the band that year. At Roadracer's insistence, the band traveled to Vancouver, Canada to record their debut album with Annihilator guitairst Jeff Waters.