Mary Isobel Catherine Bernadette O'Brien (16 April 1939 – 2 March 1999), better known by her stage name Dusty Springfield, was an English and Irish singer. With her distinctive mezzo-soprano voice, she was a popular singer of blue-eyed soul, pop and dramatic ballads, with French chanson, country, and jazz also in her repertoire. During her 1960s peak, she ranked among the most successful British female performers on both sides of the Atlantic. Her image–marked by a peroxide blonde bouffant/beehive hairstyle, heavy makeup (thick black eyeliner and eye shadow) and evening gowns, as well as stylised, gestural performances–made her an icon of the Swinging Sixties.

Born in West Hampstead in London to a family that enjoyed music, Springfield learned to sing at home. In 1958, she joined her first professional group, the Lana Sisters. Two years later, with her brother Dion O'Brien ("Tom Springfield") and Tim Feild, she formed the folk-pop vocal trio the Springfields. Two of their five 1961–63 Top 40 UK hits – "Island of Dreams" and "Say I Won't Be There"–reached No. 5 on the charts, both in the spring of 1963. In 1962, they also achieved success in the United States with their cover of "Silver Threads and Golden Needles". Her solo career began in late 1963 with the upbeat pop record "I Only Want to Be with You"—a UK No. 4 hit, and the first of her six transatlantic Top 40 hits in the 1960s, along with "Stay Awhile" (1964), "All I See Is You" (1966), "I'll Try Anything" (1967), and two releases which are now considered her signature songs: "You Don't Have to Say You Love Me" (1966 UK No. 1/US No. 4) and "Son of a Preacher Man" (1968/69 UK No. 9/US No. 10). The latter is featured on the 1968 pop and soul album Dusty in Memphis, one of Springfield's defining works. In March 2020, the US Library of Congress added the album to the National Recording Registry, which preserves audio recordings considered to be "culturally, historically, or aesthetically significant".

Between 1964 and 1969, Springfield enjoyed success in her native United Kingdom with several singles which in America either failed to chart or were not released, among them being "I Just Don't Know What to Do with Myself" (the biggest of her many Burt Bacharach/Hal David covers), "In the Middle of Nowhere", "Some of Your Lovin'", "Goin' Back", and "I Close My Eyes and Count to Ten". Conversely, she charted in the US (but not in the UK) with hits including "Wishin' and Hopin'", "The Look of Love", and "The Windmills of Your Mind". From 1971 to 1986, she failed to register a hit from five album releases (aside from a minor 1979 UK chart appearance), but her 1987 collaboration with UK synth-pop duo Pet Shop Boys, "What Have I Done to Deserve This?", took her back near the top of the charts, reaching No. 2 on both the UK Singles Chart and the Billboard Hot 100. The collaboration yielded two 1989 UK Top 20 hits: "Nothing Has Been Proved" and "In Private". In 1990, Springfield charted with "Reputation"–the last of 25 UK Top 40 hits in which she features.

A fixture on British television, Springfield presented many episodes of the popular 1963–66 British TV music series Ready Steady Go! and, between 1966 and 1969, hosted her own series on the BBC and ITV. In 1966, she topped popularity polls, including Melody Maker's "Best International Vocalist", and was the first UK singer to top the New Musical Express readers' poll for best female singer. She has been inducted into the National Rhythm & Blues Hall of Fame, the Rock and Roll Hall of Fame, and the UK Music Hall of Fame. Multiple critics and polls have lauded Springfield as one of the greatest female singers in popular music.