When “Monty Python’s Flying Circus” first began taping in London, in the fall of 1969, studio audiences were totally unprepared for what they were about to see. People brought in off the street, expecting to watch one of the BBC’s comedies or variety shows—most of them broad and campy—were given, for example, a sketch about sheep who try to fly, and how flying sheep, with the right engineering, might be made to accommodate human passengers and used for economical mass transit. Older ladies, bused in and anticipating domestic comedy—or even an actual circus—were given a play-by-play account of Pablo Picasso’s efforts to paint a masterpiece while riding a bicycle. That segment, filmed in the suburbs of London and shown to the studio audience, included references to Chagall, Miró, Brancusi, and Léger—and marked perhaps the first and only time that Kurt Schwitters has been used as a punch line. Did the audience laugh? Not much.

After the first handful of episodes aired in Britain—late on Sundays—few people knew what to make of “Monty Python’s Flying Circus.” BBC executives were concerned, the family members of the group were concerned, and, for the most part, the members of Python were concerned. “Do you realize,” John Cleese said to Michael Palin before the first taping, “this could be the first comedy show to go out with absolutely no laughs at all?” When the comedy was big and wet—sixteen-ton weights falling onto cast members, would-be soldiers killed while attacking each other with bananas and raspberries—the response was warm. Much of the time, though, the studio audiences were respectful but confused. BBC executives shuttled the show into ever-changing time slots, and hoped it would disappear...