Philip K. Dick 
Dr. Futurity 

From the author of Solar Lottery,  in a future where death is embraced, a time-traveling doctor is the only one who can save a wounded resistance leader. When Dr. Jim Parsons wakes up from a car accident, he finds himself in a future populated almost entirely by the young. But to keep the world run by the young, death is fetishized, and those who survive to old age are put down. In such a world, Parsons—with his innate desire to save lives—is a criminal and outcast. But for one revolutionary group, he may be just the savior they need to heal and revive their cryogenically frozen leader. And when he and the group journey to 1500s California, what they find causes them to question what they know about history and the underpinnings of their society. With the jarring immediacy of a car crash, Philip K. Dick throws both the reader and protagonist of Dr. Futurity into a bizarre future where healing is a crime and youth rules.