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's rival network, NBC (the broadcasting division of RCA). Many of the episodes were performed and broadcast live, but, 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.