"A Case of You" is a song by Joni Mitchell, from her 1971 album Blue. It is one of her most well-known songs.

Mitchell recorded A Case of You in 1971, during her early folk period. The song was first released on the 1971 album Blue with Mitchell playing Appalachian dulcimer, accompanied by James Taylor on acoustic guitar. The recent release of the live album Amchitka - the 1970 concert that launched Greenpeace shows that the song was written earlier than 1971 as Mitchell performs a live version of "A Case of You" at the concert. The line "I am as constant as a northern star" is a quotation from Shakespeare's play, Julius Caesar.

Mitchell later re-recorded it on her live album Miles of Aisles (1974). The song is found on Mitchell's Misses (1996), and Both Sides Now (2000) in an orchestral version featuring a new vocal by Mitchell.

The song is found on many bootleg recordings from her 1983 tour. "A Case of You" has also been performed by artists as diverse as Sloan, Tori Amos, Brian Kennedy, Michelle Branch, Keller Williams, k.d. lang, Lyn Paul, Caroline Lavelle, Kate Earl, Cristina Branco, Diana Krall, Jane Monheit, Julia Murney, Javier, Philip Morrow, Colin Meloy, Dawn Langstroth (Highwire, Linn Records), and James Blake.

Joni Mitchell, CC (born Roberta Joan Anderson; November 7, 1943) is a Canadian musician, singer songwriter, and painter. Mitchell began singing in small nightclubs in Saskatchewan and Western Canada and then busking in the streets and dives of Toronto. In 1965 she moved to the United States and, touring constantly, began to be recognized when her original songs ("Urge for Going," "Chelsea Morning," "Both Sides, Now," "The Circle Game") were covered by notable folk singers, allowing her to sign with Reprise Records and record her own debut album in 1968. Settling in Southern California, Mitchell and her popular songs like "Big Yellow Taxi" and "Woodstock" helped define an era and a generation. Her more starkly personal 1971 recording Blue has been called one of the best albums ever made. Musically restless, Mitchell switched labels and began moving toward jazz rhythms by way of lush pop textures on 1974's Court and Spark, her best-selling LP, featuring her radio hits "Help Me" and "Free Man in Paris."

Rufus McGarrigle Wainwright (born July 22, 1973) is an American-Canadian singer-songwriter and composer. He has recorded seven albums of original music and numerous tracks on compilations and film soundtracks. He has also written a classical opera and set Shakespeare sonnets to music for a theater piece by Robert Wilson.

Wainwright was born in Rhinebeck, New York, to folk singers Kate McGarrigle and Loudon Wainwright III. His parents divorced when he was three, and he lived with his mother in Montreal for most of his youth. Wainwright has dual US and Canadian citizenship. He attended high school at the Millbrook School in New York (which would later inspire his song "Millbrook"), and later briefly studied piano at McGill in Montreal. He began playing the piano at age six, and started touring at 13 with "The McGarrigle Sisters and Family", a folk group featuring Rufus, his sister Martha, his mother Kate, and aunt Anna. His song "I'm a-Runnin'", which he performed in the film Tommy Tricker and the Stamp Traveller at the age of 14, earned him a nomination for a 1989 Genie Award for Best Original Song. He was nominated for a 1990 Juno Award for Most Promising Male Vocalist of the Year.