Unfortunately, the major song-rights organizations, ASCAP and BMI, don’t keep track of this data–they’re more concerned with how many times a song is played than by how many different people. But by general agreement, the song in the rock era with the most cover versions is “Yesterday,” a Lennon/McCartney composition. (Or, as Sir Paul would prefer, given that he wrote it all by himself, a McCartney/Lennon composition.) It’s been put on wax by over two thousand different performers, including Ray Charles, En Vogue, Marvin Gaye, Merle Haggard, Elvis Presley, LeAnn Rimes, the Supremes, Tammy Wynette, and a whole bunch of different elevator-music string sections. The Gershwin ballad “Summertime,” from Porgy and Bess, however, seems to have even more versions than that–and “Silent Night,” written by Josef Mohr and Franz Gruber in 1818, may have as many as five thousand different versions on various records.

(Excerpted from the 2006 book Is Tiny Dancer Really Elton’s Little John?: Music’s Most Enduring Mysteries, Myths, and Rumors Revealed, published by Three Rivers Press, written by Gavin Edwards.)