Really surprised no one has mentioned Gore Vidal's "The City and the Pillar"; all of John Rechy's books - particularly "City of Night"; James Baldwin's books; and many of Mary Renault's Greek history novels. These were all pioneers in bringing gay themed literature to the mainstream. Although the men all presented a very dark picture of being gay, their works were indicative of the times. "The City and the Pillar" was actually re-published after many years with a more up beat ending.