Vernor Vinge's two most important books are the two large screen space operas he wrote in the 1990s--A Fire Upon the Deep and A Deepness in the Sky; the second is a loose prequel to the former, so that we know all the way through of the eventual fate of the trickster protagonist. Both are dominated by big concepts--the idea that certain technologies are only possible on the fringes of the galaxy and that the further in you go, the harder it is to think at all, let alone construct artificial intelligences; Vinge's is not a friendly universe, though some of his aliens are as likable as it is possible to be when really strange and Other. A Fire across the Deep has its action--a resurgent AI blight threatens all life--commented on by a galaxy-wide e-conference, while A Deepness in the Sky's planet-bound arachnid aliens are in some ways more like modern humans than the Earth-descended humans spying on them from space. Of his earlier novels, Marooned in Realtime is an effective murder mystery in which the victim was abandoned to live and die alone on a deserted Earth while her companions jumped further and further forward within a stasis field.