Songfacts®:

• This was inspired by a Pepsodent toothpaste commercial with the jingle, "You'll wonder where the yellow went when you brush your teeth with Pepsodent." According to group member Charles Patrick, he was in a store looking at sheet music for a different song called "Book Of Love" when the jingle came on the radio. He got the idea to combine the title with the melody from the jingle, turning "You'll wonder where the yellow went" into "I wonder, wonder who."
  
  He took the idea to two of his fellow Monotones, Warren Davis and George Malone, and they completed the song.
• Love doesn't come with an instruction manual, so this book provides one:
  
  Chapter 1: Say you love her with all your heart
  Chapter 2: Tell her you're never gonna part
  Chapter 3: Remember the meaning of romance
  Chapter 4: Break up, but give her one more chance
  
  So simple really.
• The Monotones, a doo-wop act from Newark, New Jersey, considered this song a goof and had no plans to record it, but it got a great reaction when they performed it. When they got word that a rival group was going to rip it off, they decided they had to record the song. After singing it for different record companies, they found a taker in Argo Records, which recorded and distributed it. The song was the only hit for The Monotones.
• The drum that comes in on the first line of each verse (while the line is sung a cappella) was not planned. When they were recording the song, a kid outside the studio threw a ball that hit a window just as they finished singing the "mmbadoo-ooh, who" line. They liked the way it sounded, so they decided to put a drum hit in that spot.
• Don McLean's song "American Pie" contains what is probably a reference to this in the lyric "Did you write the book of love?"
• The doo-wop throwback group Sha-Na-Na covered this on their 1969 debut album and sang it at Woodstock that same year. They went on just ahead of Jimi Hendrix.