Led Zeppelin bassist John Paul Jones composed most of this on a synthesizer. They never played the song live because Jones could not reproduce the synthesizer sound outside the studio.

Near the beginning of the song, Jimmy Page played his guitar with a violin bow. He also used the bow on "Dazed And Confused" and "How Many More Times." Talking about the song in the BBC book The Guitar Greats, Page said: "Once the vocal lines and phrasing were sorted out, you'd know where not to play, which was as important as knowing when you should play. With 'In The Light,' for instance, we knew exactly what its construction was going to be, but nevertheless, I had no idea at the time that John Paul Jones was going to come up with such an amazing synthesizer intro, plus there's all the bowed guitars at the beginning as well, to give the overall drone effect. We did quite a few things with drones on, like 'In The Evening' and all that, but when he did that start for 'In The Light' it was just unbelievable."

This was based on a song Led Zeppelin had written called "In The Morning." At one point, it was titled Originally called "Take Me Home."

A bootlegged demo of this song exists with different lyrics and opening. In that version, John Paul Jones opens with a simple sythesizer and Robert Plant starts with the lines, "Sunshine brings laughter..." (thanks, Adrian - Gettysburg, PA)

This was one of Jimmy Page's favorite songs on Physical Graffiti. In the interviews preceding the release of the album, he spoke of the song as the follow-up to "Stairway To Heaven." (thanks, Bertrand - Paris, France)