Climax! (later known as Climax Mystery Theater) is an American television anthology series that aired on CBS from 1954 to 1958. The series was hosted by William Lundigan and later co-hosted by Mary Costa. It was one of the few CBS programs of that era to be broadcast in color (using the massive TK-40A color cameras pioneered and manufactured by RCA, and used primarily by CBS' arch-rival network, NBC). Many of the episodes were performed and broadcast live, and although the series was transmitted in color, only black-and-white kinescope copies of some episodes survive to the present day. The series finished at #22 in the Nielsen ratings for the 1955-1956 season and #26 for 1956-1957.