Eleanora Fagan (April 7, 1915 - July 17, 1959), better known as Billie Holiday, was an American jazz musician and singer-songwriter with a career spanning nearly thirty years. Nicknamed "Lady Day" by her friend and music partner Lester Young, Holiday had a seminal influence on jazz music and pop singing. Her vocal style, strongly inspired by jazz instrumentalists, pioneered a new way of manipulating phrasing and tempo. She was known for her vocal delivery and improvisational skills, which made up for her limited range and lack of formal music education.

In 1935 Holiday was signed to Brunswick Records by John Hammond to record current pop tunes with Teddy Wilson in the new swing style for the growing jukebox trade. They were given free rein to improvise the material. Holiday's improvisation of melody to fit the emotion was revolutionary. Their first collaboration included "What a Little Moonlight Can Do" and "Miss Brown to You". "What a Little Moonlight Can Do" has been deemed her "claim to fame." Brunswick did not favor the recording session, because producers wanted Holiday to sound more like Cleo Brown. After "What a Little Moonlight Can Do" garnered success, however, the company began considering Holiday an artist in her own right. She began recording under her own name a year later (on the 35-cent Vocalion label), producing a series of extraordinary performances with groups comprising the swing era's finest musicians. The sessions were co-produced by Hammond and Bernie Hanighen.  With their arrangements, Wilson and Holiday took pedestrian pop tunes, such as "Twenty-Four Hours a Day" (number 6 Pop) and "Yankee Doodle Went to Town", and turned them into jazz classics. Most of Holiday's recordings with Wilson or under her own name during the 1930s and early 1940s are regarded as important parts of the jazz vocal library. She was then in her twenties.  Another frequent accompanist was the tenor saxophonist Lester Young, who had been a boarder at her mother's house in 1934 and with whom Holiday had a special rapport. He said, "I think you can hear that on some of the old records, you know. Some time I'd sit down and listen to 'em myself, and it sound like two of the same voices, if you don't be careful, you know, or the same mind, or something like that." Young nicknamed her "Lady Day", and she called him "Prez".  Hammond spoke about the commercial impact of the Wilson-Holiday sides from 1935 to 1938, calling them a great asset to Brunswick. The record label, according to Hammond, was broke and unable to record many jazz tunes. Wilson, Holiday, Young, and other musicians came into the studio without musical arrangements and improvised as they performed, dispensing with the expense of having written arrangements, so that the records they produced were cheap. Holiday was never given any royalties for her work, instead being paid a flat fee, which saved the company money. Some of the records produced were successful, such as "I Cried for You", which sold 15,000 copies. Hammond said of the record, "15,000 ... was a giant hit for Brunswick in those days. I mean a giant hit. Most records that made money sold around three to four thousand."

What happened in 1936?
Hammond spoke about the commercial impact of the Wilson-Holiday sides from 1935 to 1938, calling them a great asset to Brunswick.