It's a wonderful book for people who like this sort of book; i.e., the premise is that humans are basically too dumb to accomplish much of anything without getting a kick-start from some vastly-superior all-knowing eternally-wise civilization. It's a good story of one-dimensional characters encountering a faceless perfection; for an analogy, think of a world in which everyone is a clone of the Stepford Wives without their wit, wisdom or waxy perfection.
It does raise the question -- What would life be like if it was perfect? Clarke doesn't offer an answer, except for one young lad who wants to know more than the limits of perfect knowledge. The first two-thirds of the book set out the usual dazzling Clarke scenario; the final third degenerates into the "life is more than you can understand" formula. His city of perfection is neatly packaged in one megalopis, perhaps somewhat like the Paolo Soleri vision of FutureWorld; the element that upsets me is the assumption this vastly superior technology can't nurture a pot of geraniums outside its rigid borders.
In my view, humans always test the limits of the possible and permissable. Clarke assumes a human future where people don't color outside the lines; in contrast, anyone who's been in prison (I assume Clarke hasn't; every month I work with a dozen or so people just out of prison) knows the impossibility of living inside a closed door or blank wall.
Clarke is a classy writer, he tells intriguing stories. Personally, I don't like his sense of pessimism and deus ex machina escapism to explain the vicissitudes of mankind; but, for those who think humans need a marvelous or malevant mechanical miracle to explain our faults, future or follies . . . . Clarke is very good.
Clarke forms a world in the very distant future whose inhabitants live for hundreds of years on a ravaged planet earth in the oasis of the city. The city is an incredibly advanced utopia but an island of machines and somewhat bored inhabitants.
The main protaganist is the youngest member of the community who ventures out into a voyage of discovery and onto another community which has also survived the ravages of time. The reuniting of the two tribes of mankind each a distinct culture at opposite ends of the spectrum is problem and goal of "Against the Fall of Night".
This is science fiction storytelling at its best. A great story and a must have for all fans of the genre.