"Looking back over his life, Havelock Ellis must feel that he has assisted at a revolution in the ways of thinking and ways of living beside which many other revolutions fade into insignificance." -N. Y Herald Tribune
"Psychology of Sex represents some of the finest and, in many respects, the most advanced findings in this field; it comes as a worthy addition to Ellis' valuable bibliography." -Journal of Nervous and Mental Diseases
"The best one-volume treatment of sex in the English language." –Carl Van Doren
Havelock Ellis is, in the fullest degree, conscious of then far-reaching implications in the spheres of art, religion, and morals of the instinct whose endless permutations and aspects he is describing..." -Lencet