Most of the song was written by Doors guitarist Robby Krieger, who wanted to write about one of the elements: fire, air, earth, and water. He recalled to Uncut
: "I was living with my parents in Pacific Palisades – I had my amp and SG. I asked Jim, what should I write about? He said, 'Something universal, which won't disappear two years from now. Something that people can interpret themselves.' I said to myself I'd write about the four elements; earth, air, fire, water, I picked fire, as I loved the Stones song, 'Play With Fire
,' and that's how that came about."
Krieger came up with the melody and wrote most of the lyrics, which are about leaving inhibitions behind in flames of passion.
At first, the song had a folk flavor, but it ignited when Jim Morrison wrote the second verse ("our love become a funeral pyre...") and Ray Manzarek came up with the famous organ intro. Drummer John Densmore also contributed, coming up with the rhythm. Like all Doors songs of this era, the band shared composer credits.