Rock is a vastly popular musical genre with many complex sub-genres and descendants, which commonly features guitars and drums. It grew from the Rock & Roll and Rockabilly that emerged in the 1950s from R&B, Blues and Folk. Rock is now an umbrella term that covers a wide gamut of styles of guitar-led music. It can also be used as a suffix to emphasize Rock qualities of other styles - such as Folk Rock, Country Rock, or Funk Rock.

The late 1960s are often seen as the heyday of Rock, with bands like The Rolling Stones and Led Zeppelin emerging and becoming massively popular worldwide. Somewhat less popular were The Velvet Underground, but their albums from the same period can now be seen as massively influential on the dominant modern branch of Alternative Rock.

Prog Rock grew out of experimental tendencies of late 60s Rock bands such as Pink Floyd and King Crimson. A reaction to Prog Rock was Punk, in the mid-70s, but Punk is again a kind of Rock - faster, spikier guitars, but with a more grounded attitude than the lofty ambitions of Prog. But Punk didn't kill off Prog as some suggest: Prog just changed a little, and much Prog-related styles can still be heard today. Psychedelic Rock, favored in the 1960s by bands like Jefferson Airplane and The Grateful Dead, is related to Prog, and survives today in the shape of bands such as The Flaming Lips and Mercury Rev. What's more, a new type of Prog Rock, called Math Rock (because of its odd time signatures), emerged in the late 1980s.

Punk didn't stay static either. True punk bands are hard to come by: Post-Punk, which refined Punk's brainless guitar hacking and rebellious attitude, remains very influential today.

David Bowie, T Rex and Slade epitomized Glam Rock, which dared to add makeup and flamboyant clothes to the previously very straight and masculine Rock uniform. Glam Rock developed into Glam Metal thanks to the comedic extravagance of Kiss and Motley Crue. Meanwhile, Roxy Music were forging a line in Art Rock, which trod a path close to both Glam and Prog.

Metal is also a significant descendant of Rock: Hard Rock like Deep Purple progressed to Heavy Metal like Judas Priest, which progressed and diversified into dozens of kinds of Metal sub-genres. Hard Rock band AC/DC are one of the biggest selling bands of all time.

In the 70s and 80s, Rock bands found such success that they were able to fill stadiums in each city they played in. Bruce Springsteen's common man activism and anthemic scope made him massively popular, and bands like The Eagles, Rush, Bon Jovi and U2 also achieved similar success.

The early 90s were dominated by 'the Seattle sound', Grunge, and the incredible success of Nirvana's Nevermind moved the underground 'Alternative' Rock into the mainstream. The following years have been dominated by bands similar to Nirvana, mining the so-called Post-Grunge seam.