Mark Leslie Norton (February 7, 1956 – April 5, 2007), better known as Mark St. John, was an American guitarist best known for his brief stint with the rock band Kiss from April to November 1984. His work can be heard on the band's 1984 album Animalize. St. John died suddenly under murky circumstances in early April 2007, several months after being badly beaten during a brief stay in an Orange County jail.