Trivia

Most of "Not Only... But Also..." was erased by the BBC under their policy of wiping master videotapes (which at that time were expensive) for reuse. Only eight of the original twenty-two episodes survive complete. Peter Cook and Dudley Moore had offered to buy the BBC new tapes, but they were refused. Compilations use material from foreign networks' copies and remaining 16mm film inserts.

The show was originally intended as a solo project for Moore, called Not Only Dudley Moore, But Also His Guests. However, unsure about going it alone, Moore invited his partner from Beyond the Fringe, Peter Cook, to guest in the pilot (along with Diahann Carroll and John Lennon, who was to make two more appearances during the course of the series). So well received by the studio audience was their double act, in particular the first "Dagenham Dialogue", "A Spot of the Usual Trouble", that Cook was invited to become a permanent fixture and the show became Not Only Peter Cook and Dudley Moore, But Also Their Guests, though it was only ever really referred to as Not Only... But Also. This somewhat cumbersome title was later referred to by Cook in an interview as "another of Dudley's plodding ideas".

The opening titles for series one often featured Moore playing the series' theme (later released on the B-side of the 1965 "Goodbyee" single release) in a variety of unusual locations, such as in a car wash, on a violin at a Gypsy cafe, and as a one-man band. From series two onwards, episodes usually began with a sketch based primarily around revealing the words "NOT ONLY... BUT ALSO..." in huge letters placed in obscure places (for example, the aircraft carrier Ark Royal). Every edition except (possibly) the pilot concluded with a performance of arguably Moore's best known composition, "Goodbyee", sometimes involving the guest star of that particular episode. Examples include Cilla Black crying "Oh, kiss me, Peter!" during the song's intro in series two episode one, and Peter Sellers accompanying the duo on timpani in series one episode six.

Among the best known features of the show were the "Dagenham Dialogues" between Pete and Dud, which were rambling, surreal conversations running often for over ten minutes and regular appearances by Cook's oblivious upperclass gent, Sir Arthur Streeb-Greebling. Other well-known sketches include the "Facts of Life" sketch ("A Bit of a Chat"), "The Leaping Nuns of the Order of St Beryl", "Superthunderstingcar" (a parody of Thunderbirds and other Sylvia and Gerry Anderson puppet shows), and the "rhythmic voodoo" R&B singer Bo Dudley, though the fame of these almost certainly owes much to the fact they still exist in vision, unlike much of the series.

Contrary to popular myth, the Cook perennial "One Leg Too Few", a classic sketch about a one-legged actor applying for the role of Tarzan, which had been written by Cook when he was 18 years old and used in Beyond the Fringe, never appeared on the BBC Not Only... But Also, although it did feature in one of the Australian shows in 1971.