Havelock Ellis 
Studies in the Psychology of Sex (Barnes & Noble Digital Library) 
The Evolution of Modesty, the Phenomena of Sexual Periodicity, Auto-Eroticism

Originally published in seven volumes from 1879 to 1928, this landmark work was lawfully available only to the medical and legal profession until 1935. In his studies, Ellis sought to demystify human sexuality by exploring it from both biological and multicultural perspectives. In this volume Ellis explores the subjects sexual modesty, sexual periodicity, and autoeroticism.

About the author

Henry Havelock Ellis (1859–1939) was an English physician, sexologist, and social reformer. He conducted pioneering research that led to his momentous seven-volume work
Studies in the Psychology of Sex. His works on homosexuality, transgender psychology, narcissism and autoeroticism were groundbreaking. A supporter of women’s rights, sexual education, and sexual liberation, he did much to pave the way for researcher Alfred Kinsey and others.