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.

The Mystery of Sex by Charles Waldemar (1958)

German author discusses making of sexual union a psychic union.

Essay by Aldous Huxley (1956)

A discussion of the practice of sex without orgasm in historical terms.

The Perfect Matrimony: Why Sex and Religion are Inseparable by Samael Aun Weor (1950)

Colombian author who founded the modern Gnostic Movement shares his synthesis of sexual spiritual wisdom.

Sex Perfection and Marital Happiness by Rudolf von Urban, MD (1949)

Freudian psychiatrist explains why orgasm is not essential to sex happiness, and may be beneficial.

Thinking and Destiny: Being the Science of Man by Harold Waldwin Percival (1946)

A metaphysical look at the human condition and the role of sex.