Songfacts®:

• This celestial song was written by John Hall and his first wife, the former Johanna Schier. At the time, John was a struggling musician and Johanna was a writer for The Village Voice. Johanna was assigned an interview with Joplin, who suggested the couple write a song for her.
  
  John was working on music for a play called Line of Least Existence, and came up with a "funky, repetitive Hendrix-inspired guitar lick" for one of the tracks. After Johanna wrote the lyric, he reworked this track to fit the song and brought it to Joplin, who loved it.
  
  John got together with Joplin and her band - the Full Tilt Boogie Band - in her living room at her place in San Rafael, California, and taught them the song while her musical director, Todd Rundgren, watched. Says John, "Once guitarist John Till learned the introductory lick, which continues through most of the tune, the rest went smoothly Janis changed the lyric and melody in a few places to suit her range and style, and it rocked."
• In our interview with John Hall, he told us about this song: "It was numerological and astrological in nature. And it also had an alliterative repetition that was kind of captivating. It wasn't rhyming, exactly, but it was an internal rhyme, perhaps you could say. It's a device that poets use and that songwriters use to not just have the end of lines rhyme or the end of verses rhyme, but to have sort of a foreshadowing of that and words inside each line.
  
  So my main responsibility with that song was writing the guitar lick, which I'd say was very Hendrix inspired, and then fitting the lyric to the music. Then Janis did her own job on that, fitting it to her singing style and to her band. It was very exciting to teach it to the Full Tilt Boogie Band with Janis in her living room in Marin County, California."
• Like all the songs on Pearl, Joplin's vocal is a scratch track. These guide vocals were to be replaced by proper recordings, but she died before she had a chance to do so. Joplin typically did even her guide vocals full tilt, so there is little lacking in her performance.
• The song was used as the B-side of Joplin's #1 hit "Me And Bobby McGee." Getting "Half Moon" on a #1 single and album provided a huge windfall for the songwriters John and Johanna Hall, and gave John instant credibility, which greased the wheels of his music career. He got a gig playing guitar in Taj Mahal's band, and later formed the group Orleans, writing their biggest hits "Still The One" and "Dance With Me." Orleans recorded "Half Moon" on their 1973 self-titled debut album.
• Artists to record this song include Rufus featuring Chaka Khan, The 5th Dimension, and James Brown (as an organ instrumental).