Dr Bloodmoney Philip K. Dick
Seven years after the day of the bombs, Point Reyes was luckier than
most places. Its people were reasonably normal -- except for the girl with
her twin brother growing inside her, and talking to her. Their barter
economy was working. Their resident genius could fix almost anything
that broke down. But they didn't know they were harbouring the one man
who almost everyone left alive wanted killed . . .