The provocative and controversial science fiction novel.
Ballantine’s 1972 paperback edition of The Lovers, an early novella by Philip José Farmer that was first published by Samuel Mines in Startling Stories, August 1952. It earned him the Hugo Award for Best New SF Author or Artist in 1953 – the first of three Hugos awards he won in his career – and is “critically recognized as the story that broke the taboo on sex in science fiction.” [Wikipedia] Farmer worked it into a full-length novel in 1961.
The cover art is a (weak) reproduction of Astral Body Awake (1969) by Mati Klarwein. It’s combined with Amelia, a typeface that was popular at the time, and also appeared for other science fiction paperbacks, see e.g. Penguin’s SF series.