One of the songs that is forever tied to the rise of rock & roll is Elvis Presley's version of "Hound Dog." Originally written by Jerry Lieber and Mike Stoller for rhythm & blues singer Willie Mae "Big Mama" Thornton, the tune in its original incarnation was a modified rhumba, fueled on the original recording by an extended guitar solo from Pete Lewis. The popularity of Big Mama's version inspired an answer record on Sun by Rufus Thomas, "Bear Cat," sounding close enough to the original to inspire a lawsuit. Reportedly, Elvis got his inspiration to cover the song when he saw Freddie Bell & the Bellboys doing it in Las Vegas on an early ill-fated tour in 1956. But what Elvis did with it was entirely new and different; the beat was modified to a driving rock & roll rhythm with off-time handclaps provided by his backing singers, the Jordanaires. The guitar breaks were now kept to two 12-bar solo bursts, played effectively by Scotty Moore and, above all, the song was infused with Presley's manic vocal energy. The song blew the rock & roll movement through the roof, becoming a lightning rod for critics of the music as well as a rallying cry for the nation's youth movement. It's been successfully covered by Jerry Lee Lewis and others over the years, but nothing beats Presley's version, as emblematic a song from the '50s as you're likely to come across.