These source materials appeared between 1940 and 1960 CE.
Beyond Human Knowledge: A Consideration of the Unexplained in Man and Nature by Rudolf von Urban, MD (1958)
A physician offers his views on the electromagnetic exchange during intercourse and its potential.
German author discusses making of sexual union a psychic union.
A discussion of the practice of sex without orgasm in historical terms.
Colombian author who founded the modern Gnostic Movement shares his synthesis of sexual spiritual wisdom.
Freudian psychiatrist explains why orgasm is not essential to sex happiness, and may be beneficial.
A metaphysical look at the human condition and the role of sex.