For that is the genius of the old man — Tolstoy teaches us that compassion is of value and enriches our life only when compassion is severe, which is to say when we can perceive everything that is good and bad about a character but are still able to feel that the sum of us as human beings is probably a little more good than awful... That fine edge in Tolstoy, the knowledge that compassion is valueless without severity (for otherwise it cannot defend itself against sentimentality), gave The Naked and the Dead whatever enduring virtue it may possess and catapulted the amateur who wrote it into the grim ranks of those successful literary men and women who are obliged to become professional in order to survive....

Mailer's Introduction to the 50th Anniversary Edition - The Naked and the Dead (1948)