Rock music is a style of music derived from the blues, characterised by a prominent drum beat in 4:4 time, accompanied by electric bass guitar providing the harmonic underpinning for the melody of electric guitar and vocals.
Elvis Presley and Buddy Holly were early pioneers of Rock in the late 1950's, as were the Beatles and Rolling Stones throughout the 1960s. In the 1970s the stadium rock of bands such as Boston and Pink Floyd became formulaic and overwrought, setting the stage for a backlash called Punk rock which evolved, with the addition of synthesizers, into New wave well into the 1980s. By the latter half of that decade, Glam rock had stultified into MTV-friendly "hair metal", and the stage was set for Nirvana and the Seattle scene, a darker and heavier version of punk known as Grunge. By 1994 and the death of Kurt Cobain, grunge had changed into the stable formula of alternative rock that continues to be popular today.