McCann is clearly carving out a niche in writing about the "Golden Age" of British sitcoms - this and his book on Dad's Army are only two out of many.
McCann begins with the origins of the programme, and this is perhaps the most interesting section in that it is original material. For the Yes Minister story, we are in fact taken back to 1962, and the peculiar case of Sir Frank Soskice, who petitioned the Home Secretary for a posthumous pardon in a death penalty case, only to deny such a request on becoming Home Secretary himself. Some ten years later, Antony Jay and Jonathan Lynn met when working with John Cleese; and when Cleese moved on to write Fawlty Towers (the subject of another of McCann's books), the two began to work more closely, and on a recollection of the Soskice case and other bureaucratic absurdities, began considering the idea of a sitcom centred around government.
For a while it was just an idea; then, with the publication of the Crossman Diaries and Leslie Chapman's Your Disobedient Servant, the pair became more active. The BBC was interested, and a pilot episode was produced in early 1979 and favourably received. But then, it was felt that the policital climate was not quite right, with the Winter of Discontent and following general election. So the first series was postponed, and due to other commitments for the cast, delayed until about a year later.
The main part of the book covers the three series of Yes Minister, the Christmas special Party Games, and the two series of Yes Prime Minister. It's not an episode-by-episode guide, but rather McCann's selection of the highlights, the topical themes, unlikely stories originating from fact or predicting future events, and the more dry subject matter of viewing figures. There's an attempt to go searching for dirt, but none is really found: the writers, the main cast and the directors all got on well. The most McCann can find is Nigel Hawthorne's awkwardness at regularly beating Paul Eddington for BAFTA prizes (perhaps particularly since Eddington, on reading the initial scripts, indicated a preference for the role of Sir Humphrey himself). Jay and Lynn had generally opposing political views, which may have helped focus the writing in a way that eliminates overt party bias in the stories.
The final section touches on the series' legacy, including its revival on stage in 2010 and in 2013 on Gold to mixed reviews (I haven't seen that series). But there's no doubt that the "classic" series is now embedded in British culture, playing cleverly on the politician's desire to do the "right" (i.e. popular) thing, and the civil servant's desire to do the "right" thing (favouring stability, precedent and continuity). Poignantly, whilst Eddington and Hawthorne both died many years ago, McCann had a lot of contact with Derek Fowlds, which is reminiscent of the novelisations (which feature Hacker's diary, excerpts from the Appleby papers, and conversations with Sir Bernard Woolley).