John William Stevenson (born September 10, 1963) is an American musician and record producer. He is the drummer, main songwriter, and the only constant member of the California punk rock group Descendents since its inception. In late December 1981, he played a few concerts with the hardcore punk band Black Flag because their drummer ROBO was detained in England after a tour there. He went on to record with Black Flag on several of their albums until 1985, including the highly influential My War. After this he focused his attention on Descendents and played with the band until lead singer Milo Aukerman left in 1987. After Milo's departure, Bill and the other members of Descendents, Karl Alvarez and Stephen Egerton, recruited singer Dave Smalley of Dag Nasty, moved to Fort Collins, Colorado,