This one a post-apocalyptic number called Eternity Road. Different story, same problems: good characters, smooth writing, okay plot -- and utterly no grasp of the failure modes or speed of decay of concrete and asphalt roads in a midwestern- and northeastern-U.S. climate. Additionally, the characters have books (including a precious few ancient printed ones), jewelers and gunsmiths but not moveable type; they understand what concrete is (there's a trick or two to concrete and the secret has been found and lost many times in human history) and take it for granted. And so on. At one point, a character describes a steam engine -- all except for the actual engine!
He doesn't know what he doesn't know. If he's dealing with technology so advanced it might as well be magic, he does fine. If he's dealing with primitive tech, he does fine. Stick him in an 19th-Century machine shop or a 20th-Century electronics lab and he's lost.
Well-written books if you're an English major. If you want to read post-apocalypsos you can dance to, try Kim Stanley Robinson's The Wild Shore or Stewart's Earth Abides. Andre Norton liked the general theme, too, and had a better eye for what lasts and what doesn't.
3 months ago