In 1966, Eddie Floyd had been a staff writer and producer for a year at Stax Records, the legendary Memphis pop, soul and R&B label of Otis Redding, Sam and Dave and Booker T. & the MGs Working with Stax guitarist Steve Cropper, Floyd had already written two hits for Wilson Pickett: “634-5789 (Soulsville, USA)” and “Ninety-Nine and A Half (Won’t Do)”. Cropper had also co-written with Pickett the singer’s “In the Midnight Hour”.

One night in 1966, he and Cropper set out to write a song about luck and superstition at the Lorraine Motel in Memphis. Floyd worked with the superstition that if you knock on wood after expressing a hope or wish (“I hope I win the lottery, I knock on wood”), it will come true.

The belief goes back to the first cultures that believed that living things like trees had mystical powers; when cut, the wood lost its magical qualities. Touching, for example, a wooden table is supposed to drive away the evil spirits that inhabit the wood.

Loud thunder and the lightning that followed gave Floyd the line “Like thunder, lightning, the way I love you is terrifying.” The addition of the line helped shift the tune’s focus from luck to love.

The song the couple wrote was “Knock on Wood”. To Floyd’s lyrics, Cropper contributed the song’s signature intro. Cropper’s inspiration was his own “In The Midnight Hour”. For “Knock on Wood”, Cropper played the intro to “Midnight Hour” backwards.

Believing they had written a hit for Otis Redding, Floyd and Cropper went to the studio the next day to record a demo of “Knock on Wood”. Issac Hayes contributed the trumpet arrangement and Al Jackson came up with the distinctive four “beats” on drum that follow Floyd’s “You Gotta Play…”.

But Stax founder Jim Stewart believed the song mimicked “In The Midnight Hour” and refused to let Redding record it. The demo sat untouched on the can for months until Stewart could be convinced to release the record as an Eddie Floyd song.

The “Knock on Wood” demo would become the final version that everyone knows today; it was never re-edited for release as a single.

“Knock on Wood” would become the biggest hit of Floyd’s career and has been covered by more than 100 artists, including Eric Clapton and Seal; Amii Stewart’s disco version topped the charts in 1979.

And despite Jim Stewart’s initial opinion of the song, Otis Redding would record “Knock on Wood” in 1967 as a duet with Carla Thomas.