As/Is is a live album by John Mayer, released October 19, 2004, available for download from iTunes and also available as a double-CD release. The albums were released from live concert performances across the United States from the tour following the release of Mayer's second album, Heavier Things. The recordings include five albums-worth of material as sold on iTunes. As of July 2009, the four concert-specific albums were still available on iTunes in the United States, though Volume One is no longer available; Each album has its own artwork. A two-disc compilation was released physically and digitally which features the "best" of the iTunes series, plus an additional song, "Inner City Blues ", a Marvin Gaye cover. In "Inner City Blues", Mayer called upon DJ Logic, the support act of the Heavier Things tour, to join him to perform a turntable solo.

John Clayton Mayer is an American singer, songwriter, and guitarist. He attended Berklee College of Music in Boston, but he left for Atlanta in 1997 with fellow guitarist Clay Cook, with whom he formed the short-lived rock duo, Lo-Fi Masters. After their split, Mayer continued to play at local clubs, refining his skills and gaining a minor following. He performed at the 2000 South by Southwest festival, and was subsequently signed by Aware Records, an imprint of Columbia Records through which he released his debut extended play (EP), Inside Wants Out (1999). His first two studio albums—Room for Squares (2001) and Heavier Things (2003)—were both met with critical and commercial success; the former won a Grammy Award for Best Male Pop Vocal Performance for its single "Your Body Is a Wonderland", while the latter peaked atop the Billboard 200.