Van Halen in the context of Kool and the Gang

Heavy metal (or simply metal) is a genre of rock music that developed in the late 1960s and early 1970s, largely in the United Kingdom and United States. With roots in blues rock, psychedelic rock and acid rock, heavy metal bands developed a thick, monumental sound characterized by distorted guitars, extended guitar solos, emphatic beats and loudness.

In 1968, three of the genre's most famous pioneers – British bands Led Zeppelin, Black Sabbath and Deep Purple – were founded. Though they came to attract wide audiences, they were often derided by critics. Several American bands modified heavy metal into more accessible forms during the 1970s: the raw, sleazy sound and shock rock of Alice Cooper and Kiss; the blues-rooted rock of Aerosmith; and the flashy guitar leads and party rock of Van Halen. During the mid-1970s, Judas Priest helped spur the genre's evolution by discarding much of its blues influence, while Motörhead introduced a punk rock sensibility and an increasing emphasis on speed. Beginning in the late 1970s, bands in the new wave of British heavy metal such as Iron Maiden and Saxon followed in a similar vein. By the end of the decade, heavy metal fans became known as "metalheads" or "headbangers". The lyrics of some metal genres became associated with aggression and machismo, an issue that has at times led to accusations of misogyny.

Hard rock or heavy rock is a heavier subgenre of rock music typified by aggressive vocals and distorted electric guitars. Hard rock began in the mid-1960s with the garage, psychedelic and blues rock movements. Some of the earliest hard rock music was produced by the Kinks, the Who, the Beatles, the Rolling Stones, Cream, Vanilla Fudge, and the Jimi Hendrix Experience. In the late 1960s, bands such as Blue Cheer, the Jeff Beck Group, Iron Butterfly, Led Zeppelin, Creedence Clearwater Revival, Golden Earring, Steppenwolf, Grand Funk Railroad, Free, and Deep Purple also produced hard rock.

The genre developed into a major form of popular music in the 1970s, with the Who, Led Zeppelin and Deep Purple being joined by Black Sabbath, Alice Cooper, Aerosmith, Kiss, Queen, AC/DC, Thin Lizzy and Van Halen. During the 1980s, some hard rock bands moved away from their hard rock roots and more towards pop rock. Established bands made a comeback in the mid-1980s and hard rock reached a commercial peak in the 1980s with glam metal bands such as Mötley Crüe, Bon Jovi and Def Leppard as well as the rawer sounds of Guns N' Roses which followed with great success in the later part of that decade.