Sandy Denny (6 January 1947 – 21 April 1978), born Alexandra Elene Maclean Denny, was an English singer and songwriter who has been described by Allmusic's Richie Unterberger as "the pre-eminent British folk rock singer".
Denny is considered a founder of the British folk rock movement and perhaps its most important female singer, songwriter and personality. Over a ten-year career Sandy Denny left an extensive legacy and remains influential. She is remembered for her pivotal involvement with the British folk rock scene, where, as a member of Fairport Convention, she moved the band away from west coast American cover versions and into performing traditional material and original compositions.
Denny is also remembered as a composer most notably on her solo albums which represent her claim to be Britain's finest female singer-songwriter, as asserted by the Sunday Express, Uncut and Mojo. Her composition, "Who Knows Where the Time Goes?", has been recorded by numerous artists as diverse as Judy Collins, Nina Simone and Cat Power and is now regarded as a classic. Famous also for her exceptional voice, it has been suggested that her effortless and smooth vocal delivery still sets the standard for many of today's female folk-based singers.
She is also noted for her duet with Robert Plant on the song "The Battle of Evermore" from Led Zeppelin's fourth album released in 1971. She remains to this day the only guest vocalist on a Led Zeppelin album.