Eva Marie Cassidy (February 2, 1963 – November 2, 1996) was an American vocalist known for her interpretations of jazz, blues, folk, gospel, country and pop classics. She released her first album The Other Side, a set of duets with go-go musician Chuck Brown in 1992 followed by a live solo album, Live at Blues Alley in 1996. Cassidy was virtually unknown outside her native Washington, DC when she died of melanoma in 1996.

Four years later, Cassidy's music was brought to the attention of UK audiences when her versions of "Over the Rainbow" and "Fields of Gold" were played on BBC Radio 2. Following the overwhelming response, a camcorder recording of "Over the Rainbow" taken at the Blues Alley was shown on BBC Two's Top of the Pops 2. Shortly after, the compilation album Songbird, climbed to the top of the UK Albums Charts, almost three years after its initial release. The chart success in the United Kingdom led to increased recognition worldwide; as of 2003, her posthumously released recordings, including three UK #1s, have sold around six million copies. Her music has also charted top 10 positions in Australia, Germany, Sweden, Norway and Switzerland.

After Cassidy's death, local folk singer Grace Griffith introduced the Blues Alley recording to Bill Straw from her label, Blix Street Records.  Straw approached the Cassidy family to put together a new album. In 1998, a compilation of tracks from Cassidy's three released recordings was assembled into the CD Songbird. This CD lingered in relative obscurity for two years until being given airplay by Terry Wogan on his wide-reaching BBC Radio 2 show Wake Up to Wogan, following recommendation by his producer Paul Walters. The album sold more than 100,000 copies in the following months. The New York Times spoke of her "silken soprano voice with a wide and seemingly effortless range, unerring pitch and a gift for phrasing that at times was heart-stoppingly eloquent".

Before Christmas of 2000, Top Of The Pops 2 aired a video of Cassidy performing "Over the Rainbow", which resulted in Songbird climbing steadily up the UK charts over the next few weeks. Just as ITV's Tonight with Trevor McDonald aired a feature on Cassidy, the album topped the chart. Shot at Blues Alley by a friend with a camcorder the same night the album was recorded, the black-and-white video became the most requested video ever shown on Top Of The Pops 2. "There's an undeniable emotional appeal in hearing an artist who you know died in obscurity singing a song about hope and a mystical world beyond everyday life", wrote The Guardian.

Songbird has since achieved significant chart success throughout Europe and quadruple platinum status in the UK. Although still relatively unknown in the United States at that time, the album would eventually be certified gold. Sherri Dalphonse of Washingtonian.com writes, "Some may wonder if Cassidy's death at the age of 33 accounts for some of the popularity. No doubt her life story is part of it. But articles about her haven't boosted sales as much as when her songs are played on the BBC or NPR. Hearing about Eva Cassidy isn't as powerful as hearing her." Since Songbird, several other CDs have been released: Time After Time (2000), Imagine (2002) and American Tune (2003).

In May 2001, ABC's Nightline in the United States broadcast a well-received short documentary about Cassidy. Over the weekend, all five of Cassidy's albums occupied Amazon.com's best sellers list top spots. The Nightline episode has since been rebroadcast three times due to popular demand.Producer Leroy Sievers has said that it is "probably the most popular Nightline ever". A rebroadcast of the Tonight with Trevor McDonald feature on Cassidy in Britain resulted in a similar sales surge. Together with word of mouth and internet fansites, the role of online commerce has played a big part in Cassidy's success. This point was further affirmed when in 2005, Amazon.com released a list of its top 25 best-selling musicians, which placed Cassidy in 5th position, behind The Beatles, U2, Norah Jones and Diana Krall.

In 2004, during the gala opening of the Bowie Center for the Performing Arts, the Bowie Regional Arts Vision Association, Inc. (BRAVA) dedicated the Star's Dressing Room to Eva. Following a moving tribute to Eva, Chuck Brown took to the stage and performed his duet "with" Eva as her photos and video appeared in the background.