Bill "Mad Dog" Madlock, Jr. is an American former professional baseball player and coach. He played in Major League Baseball as a third baseman from 1973 to 1987. Madlock is notable for being a four-time National League batting champion. His four batting titles as a third baseman was a record until Wade Boggs attained his fifth in 1988. Since 1970, only Tony Gwynn has won more National League batting titles (eight). Madlock is also one of only three right-handed hitters to have won multiple National League batting titles since 1960, Roberto Clemente having also won four and Tommy Davis having won back-to-back titles in 1962 and 1963.