Though third in chronological sequence, this was the first of the About Time series published, covering precisely the years of Jon Pertwee as the third Doctor, and almost as precisely the years of Barry Letts as producer and Terrance Dicks as script editor. It's a huge change of setting for the show with almost two thirds of the 24 stories - including the whole of the first Pertwee season - set on contemporary Earth with the UNIT team. (Compare precisely one contemporary adventure, plus some odd bits and pieces [including the first ever episode], of the 29 Hartnell stories, and a fairly steady rate of 10-20% for the remainder of the classic series; compare, of course, also 100% of the eighth Doctor's on-screen adventures, and a third of the stories since the 2005 revival.)
Miles and Wood have done a very good job of identifying the roots of each story, literary, political and televisual. It's not yet at the levels of genius that their Volume 2 reached, but there are some glorious moments, including the frightening similarities between Jon Pertwee, Jimmy Saville and Bruce Forsythe. They have also yet to give in to the unfortunate enthusiasm for endnotes which is one of the few really annoying things about later volumes. (The five fairly restrained end-notes here concern Enoch Powell, Oswald Mosley, Sooty and Sweep, the aforementioned Bruce Forsythe, and Catweazle.) There are the usual discursive essays, of which the two best are probably on the importance of the incidental music and on the implied history of UK politics in Doctor Who.
Anyway, I've ordered the more cerebral-looking Time and Relative Dissertations in Space: Critical Perspectives on Doctor Who, which Amazon seems to think will be available this coming week, but it has a tough act to follow.