The Avengers (which appeared on ABC from 1961 to 1969) has the distinction of being the most popular British television series to run on an American commercial network, and was the first such series to do so in prime time. Sophisticated, tongue-in-cheek, but never camp or silly, The Avengers was also one of the first and best of the soon-to-be-popular television spy series, and varied in tone from crime melodrama to outright science fiction. Every episode starred John Steed (Patrick Macnee), an urbane British intelligence agent who heads a mysterious elite squad known as the Avengers, so named for their propensity to right wrongs.

The first four seasons of the show were not run in the United States, but were videotaped and aired only in Britain. The series began as a follow-up to Police Surgeon (1960), which starred Ian Hendry as a doctor who helped the police solve mysteries...