https://en.wikipedia.org/wiki/What_Is_This_Thing_Called_Love%3F https://www.learnjazzstandards.com/jazz-standards/what-is-this-thing-called-love/ Found on: The Real Book Vol 1 pg. 460 Found on: The Colorado Cookbook pg. 265 Original key: F minor Written by Cole Porter, for the musical Wake Up and Dream in 1929