The series suffered from the BBC's lack of a proper archiving policy until 1978. It was BBC policy before 1978 to wipe master tapes and reuse them for other programmes, hence saving money and storage space. Twelve episodes out of the twenty-nine made for this series are believed to no longer exist; those that do are 16mm film sales copies. Season 1 is almost complete with only one episode missing (Ticket to Terror (1966)), whilst Season 2 is almost completely missing with only two episodes surviving (Black Echo (1967) and A Sinister Sort of Service (1967)). In 2003, D for Destruction (1966), the Season 1 finale episode, was found by the BBC in a mislabeled film can. The complete audio soundtrack for The Basardi Affair (1967) was recovered in 2017.
In the series' original pilot episode the part of Georgie was played by Ann Holloway. Although elements of the pilot were used in the existing opening instalment, there is currently no known copy of this untransmitted edition in existence.
In 2002, the long-running CBBC magazine show Blue Peter (1958) ran an eight part Victorian era drama called "Quest II: The Hunt for the Blue Stone". Gerald Harper appeared, whilst the mysterious whispering villain, whose face was concealed behind a mask, was tellingly called The Visage. The serial also tipped its hat to The Avengers (1961) and The Prisoner (1967).
Noted comedy writer Dick Vosburgh supplied, uncredited, ex-vaudevillian Simms' array of limericks throughout the series.
The opening graphics for Adam Adamant Lives were created by Bernard Lodge. He also created the opening graphics for Doctor Who.