Perry Mason is an attorney who specializes in defending seemingly indefensible cases. With the aid of his secretary Della Street and investigator Paul Drake, he often finds that by digging deeply into the facts, startling facts can be revealed. Often relying on his outstanding courtroom skills, he often tricks or traps people into unwittingly admitting their guilt. The original TV series was first broadcast on CBS on September 21, 1957. The series first started shooting in October, 1956. It was based on the famous "Perry Mason" books written by Erle Stanley Gardner. Running from September, 1957 until May 1966, the series had 271 episodes. All but one episode were filmed in black and white. The only color episode was called "The Case of The Twice-Told Twist", which was also the series finale.