I would like to mention
Ernest Hemmingway
esp.:
To Whom The Bells Toll

Undependingly from beeing a great Author Hemmingways
shows a very good insight into realistic human behavior.
What makes the story different fom others is, that
Hemmingway doesn't write much about emotions
directly, but one can always conclude from the
action of the characters and their dialogues.
This sends the reader into the position of a very
informed spectator, which works good with erotic fiction,
too, I guess.