From the late 1960s it became common to divide mainstream rock music into soft and hard rock. Soft rock was often derived from folk rock, using acoustic instruments and putting more emphasis on melody and harmonies. Major artists included Carole King, Cat Stevens and James Taylor. It reached its commercial peak in the mid- to late- 70s with acts like Billy Joel, America and the reformed Fleetwood Mac, whose Rumours (1977) was the best selling album of the decade. In contrast, hard rock was more often derived from blues-rock and was played louder and with more intensity. It often emphasised the electric guitar, both as a rhythm instrument using simple repetitive riffs and as a solo lead instrument, and was more likely to be used with distortion and other effects. Key acts included British Invasion bands like The Who and The Kinks, as well as psychedelic era performers like Cream, Jimi Hendrix and The Jeff Beck Group. Hard rock-influenced bands that enjoyed international success in the later 1970s included Queen, Thin Lizzy, Aerosmith and AC/DC.
