Sometimes when you read literary journalism, you think, ''But how could the writer know his subject 'blinked twice in rapid succession'? He wasn't there!'' That doesn't happen with Mike Sager's work. In Revenge of the Donut Boys' pieces, which are mostly from Esquire, Sager writes in convincingly novelistic detail and supple, pinpoint prose about the inner lives of a high school junior, a 92-year-old man, Slayer fans, swingers, struggling actors, Mike Ditka, and wildfire victims. The title piece is one of his best, the short true story of some car-stealing Newark kids. ''They'll rustle up a car,'' Sager writes, ''to drive to elementary school, in lieu of bus fare.''