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.^[1]

In February 1955, Martin Manulis became the producer, replacing Bretaigne Windust. The trade publication Variety reported that the change in producers would be accompanied by a change in format. It said, "The sponsor, Chrysler, has been discontent with the restrictive suspense-horror formula," and that future episodes would be "designed to accent adventure and emotional climaxes rather than stark melodrama".^[2]

In 1954, the Climax! episode "Casino Royale" featured secret agent James Bond in a television adaptation of Ian Fleming's novel Casino Royale. It starred Barry Nelson as American secret agent "Jimmy Bond" and Peter Lorre as the villain Le Chiffre. It was the first screen adaptation of a James Bond novel, made before Eon Productions acquired the Bond film rights. Eon would later obtain the rights to Casino Royale in the late 1990s. This adaptation is available on DVD as a bonus feature on the MGM DVD release of the 1967 film adaptation of the novel.

The only other episode of Climax! available on DVD is Gore Vidal's adaptation of Robert Louis Stevenson's The Strange Case of Dr. Jekyll and Mr. Hyde, retitled on Climax! as "Dr. Jekyll & Mr. Hyde".^[3] It stars Michael Rennie, Sir Cedric Hardwicke and Lowell Gilmore. It is available in the DVD box set Classic Sci-Fi TV—150 Episodes from Mill Creek Entertainment.^{[citation needed]}

In an earlier episode of Climax!, an adaptation of Raymond Chandler's The Long Goodbye, actor Tristram Coffin, playing a dead body, arose in-shot and walked offstage. The event was widely covered in the media of the day, later becoming an urban legend that was attributed to Peter Lorre and the aforementioned adaptation of Casino Royale.^[4]

In addition, a small number of episodes from the series can be found on YouTube.^{[citation needed]}

(In alphabetical order)