To what extent does A Separate Peace reflect the turbulent life of the author?

While not exactly an autobiographical book, A Separate Peace reflects John Knowles's high school years at the exclusive Philips Exeter Academy, a New England boarding school on which the novel's Devon school is very closely modeled. Knowles attended the Exeter Academy during the same years as his characters, so the turbulent backdrop of World War II and the teens' anxieties about joining the army were also part of Knowles's adolescence.
Knowles based Phineas on David Low Hackett, who was a friend of Robert Kennedy, and Gore Vidal has stated that Knowles told him he was the model for Brinker. Like Gene, we can see that Knowles circulated in a rarified upper-class circle of privilege.
While most of the incidents in the novel are imaginary, the anxiety about war and the future of the world that hangs over the high school boys reflects the emotional reality of Knowles's times. Characters like Leper, who could not handle the army, or like Phineas, who could not hope to serve due to injuries, mirror real situations of a period dominated by war and uncertainty.