The bedrock of David Guetta's Nicki Minaj-featuring single "Hey Mama" is a sample of "Rosie," a 1940s prison recording from folk archivist Alan Lomax that songwriter Esther Dean first showed the French DJ on YouTube.
The love is growing in the '70s hit "Love Grows (Where My Rosemary Goes)" because rosemary is the name of an herb.
Dr. Luke and Max Martin originally wrote Kelly Clarkson's "Since U Been Gone" with Pink in mind but she turned it down.
Nelly's "Country Grammar" is a celebration of his hometown of St. Louis, which some folks from the coasts consider "country" because it's in the Midwest.
Billy Joel's "My Life" was used as the theme song to the 1980 TV show Bosom Buddies, which starred a young Tom Hanks as a guy who lives in a hotel for women by dressing up as a girl.
Miley Cyrus didn't write "Wrecking Ball" but could very much relate to it. She was having problems in her relationship with Liam Hemsworth, so the theme of giving your love only to have it wrecked really resonated with her.
The lead singer and pianist for Procol Harum, Gary talks about finding the musical ideas to match the words.
How well do you know this shock-rock harbinger who's been publicly executed hundreds of times?
The lead singer on "Da Doo Ron Ron" and "Then He Kissed Me," La La explains how and why Phil Spector replaced The Crystals with Darlene Love on "He's A Rebel."
When you free your mind, your ass may follow, but you have to make sure someone else doesn't program it while it's wide open.
"Lullaby" singer Shawn Mullins on "Beautiful Wreck," beating the Devil, and his writing credit on the Zac Brown Band song "Toes."
A top country songwriter, Barry talks about writing hits for Little Big Town, Tim McGraw and Jason Aldean.