Back in the days before video recorders, let alone DVDs, Doctor Who stories lived on after first broadcast only in the novelisations published by Target Books (and later by Virgin). In the fullness of time, almost every story ever shown appeared in print - many of them in novelisations by the indefatigable Terrance Dicks, whose lucid if workmanlike style informed the tastes of a generation of fans.
One of the few stories not to get that treatment was the 1979 Fourth Doctor story City of Death, which has a strong claim to being one of the best Who stories ever, written over a wet weekend by the then script editor Douglas Adams, certainly the most prominent SF writer to have held that position, from a story concept by David Fisher, one of the best Who writers of the late 1970s. It is now brought to the page by James Goss, who I personally rate as the best writer of Who prose and audios active at present. (He has, alas, no screenplay experience, so I don't expect him to be writing any TV episodes soon.)
Goss is not the first Who writer to try and channel Douglas Adams (unsuccessful: Eric Saward; successful: Gareth Roberts). But he takes it in a new direction, starting off by lulling the reader into a false sense of security with an Adams-esque first chapter, and then settling into adapting from both the script and the final broadcast version for the printed page. As he explains in an afterword, he picks and chooses between the alternatives. Shakespeare here sprained his hand playing croquet (Adams) rather than writing sonnets (Tom Baker's improvisation). The John Cleese and Eleanor Bron characters have been pursuing a desultory love affair around Paris for days. Most importantly, the Count doesn't actually realise his own identity until the end of the first episode, and this actually makes a lot of sense. (But he keeps the broadcast version of the story's funniest line, while explaining how it originated from the script.)
The target audience for this book will be people who already know the story, and I think that they will be satisfied. It's a different situation from Shada, the unfinished 1980 story by Adams whose novelisation by Gareth Roberts was published in 2012, in that there's no what-might-have-been mystery about City of Death - we've seen it and we know what happens. Goss preserves the spirit of Adams' script, and probably does a better job of putting it on the page than Adams would have done (he had a habit of revising his own past work without necessarily improving it).
Anyway, for those of us who treasure memories of a former monk from Liverpool courting an Ulster aristocrat by the Seine, this is simply indispensable. And for those who are fans of Douglas Adams, this is, in a way, his last book, reflecting back to the height of his powers. I won't claim that it's great literature; but I loved it.