The Big Bang Theory is an American sitcom created by Chuck Lorre and Bill Prady, both of whom serve as executive producers on the show, along with Steven Molaro. All three also serve as head writers. It premiered on CBS on September 24, 2007.
The show is centered on five characters: roommates Leonard Hofstadter and Sheldon Cooper, two physicists who work at the California Institute of Technology (Caltech); Penny, a blonde waitress and aspiring actress who lives across the hall; and Leonard and Sheldon’s equally geeky and socially awkward friends and co-workers aerospace engineer Howard Wolowitz and astrophysicist Rajesh Koothrappali. The geekiness and intellect of the four guys is contrasted for comic effect with Penny’s social skills and common sense.
Three other supporting characters have also been promoted to starring roles: Leslie Winkle, a physicist colleague at Caltech and, at different times, a lover of both Leonard and Howard who left the show after season 3; Bernadette Rostenkowski, Howard’s fiancée, who is a microbiologist and former part-time waitress alongside Penny; and Amy Farrah Fowler, a neurobiologist who joins the group after being matched to Sheldon on a dating website.