
When cabdriver Dave Rudman's wife of five years deserts him for another man, taking their only child with her, he is thrown into a tailspin of doubt and discontent. Fearing his son will never know his father, Dave pens a gripping text--part memoir, part deranged philosophical treatise, and part handbook of "the Knowledge" learned by all London cab drivers. Meant for the boy when he comes of age, the book captures the frustration and anxiety of modern life. Five hundred years later, the Book of Dave is discovered by the inhabitants on the island of Ham, where it becomes a sacred text of biblical proportion, and its author is revered as a mighty prophet.
Also see The Book Of Dave, although it's no match for Riddley.
It's an incredible book in particular if you know London and have been in a black cab and heard the sorts of banter London taxi drivers use, because in the "future" section everyone speaks in a corrupt English dialect based on this. You can also spot various London landmarks in the post-apocalyptic setting (eg the Centerpoint building).
HNers who are into Sci-Fi ought to check out Will Self's "The Book of Dave", which is funny, brilliant, and (in large part) about a future post-apocalyptic society which makes a religion of "The Knowledge."
Another example (slightly obscure) from London is "The Book of Dave" by Will Self, which is partly set in a post-apocalyptic future. The geography is very thoughtfully handled, but in this future the Thames has flooded and lots of London is underwater. Part of the fun is figuring out which bits of present London they are referring to when they talk about landmarks etc which survive[1].
Now it's fair to say all those examples are shooting a lot higher-brow than Dan Brown, but another example more similar in genre aesthetic to Dan Brown would be John LeCarre's "Smiley" novels (eg "The spy who came in from the cold" etc). To the extent I know the locations in the ones I have read, they seem to me very authentically described, which greatly enhances my sense of immersion in the atmosphere.
[1] eg "centrul stack" I'm pretty sure is the wreck of the Centerpoint Building, now an empty shell filled with seabirds.
