William Bruce Davis is a Canadian actor, best known for his role as the Cigarette Smoking Man on The X-Files. Besides appearing in many TV programs and movies, he founded his own acting school, the William Davis Centre for Actors Study. In his personal life, he is an avid water-skier, lectures on skepticism at events such as the Committee for Skeptical Inquiry's CSICon, and advocates for action on climate change. In 2011 he published his memoir, Where There's Smoke ... The Musings of a Cigarette Smoking Man.

The Cigarette Smoking Man is a fictional character and one of the primary antagonists of the American science fiction drama television series The X-Files. He serves as the arch-nemesis of FBI Special Agent Fox Mulder. In the show's sixth season, his name is said to be C.G.B. Spender, but Dana Scully suggests this is one of "hundreds of aliases"; the show's characters and fans continue to refer to him by variations of "the Smoking Man" because he is almost always seen chain-smoking Morley cigarettes, and because he was credited in the pilot episode and other episodes as "Smoking Man". In the eleventh season, he reveals his full name to be Carl Gerhard Busch.