Search - The Dark Beyond the Stars

This one is reccommended by my wife as "the best 'hard' science fiction novel I've ever read." A generation ship has been seeking life elsewhere in the Universe for two thousand years, and the ship is slowly breaking down over the course of the long years…while the Captain, immortal and obsessed, is determined to take the ship into the Dark (a starless void between the arms of the Galaxy). It certainly left an impression when I read it: it's a believable look at an aspect of science fiction that doesn't receive as much attention as it deserves, with an emphasis on character development and believable science. This was apparently the only major science fiction novel written by this author before his death.