Marooned in Realtime is a 1986 murder mystery and time-travel science fiction novel by American writer Vernor Vinge, about a small, time-displaced group of people who may be the only survivors of a technological singularity or alien invasion. It is the sequel to the novel The Peace War (1984) and the novella The Ungoverned (1985). The two novels and the novella were collected in Across Realtime.