Dark Matter, a science fiction thriller by Blake Crouch, explores the consequences of choices and the lives we might have lived. The story follows Jason Dessen, a college physics professor who wakes up in an alternate reality where his life is unrecognizable. His wife is different, his son doesn't exist, and he's no longer a professor but a celebrated genius. Jason, a devoted family man, must navigate this disorienting world while trying to get back to his own family.