Studies in the Psychology of Sex: Volume 7 is a book published in 1928 by the English physician and writer Havelock Ellis (1859–1939). Ellis was an expert of human sexuality but was impotent until the age of 60 and married to an open lesbian for much of his life. He later discovered that he could be aroused by the sight of a woman urinating. Terming this sexual deviation undinism, it is one of several topics covered in the seventh and final volume of his studies in the psychology of sex. Ellis began writing the first of the seven books in 1900, exploring topics such as sexual inversion (homosexuality), sexuality in women, and erotic symbolism throughout the volumes. Volume seven was originally published in the United States due to the stigma surrounding transgenderism, homosexuality, and other sexual deviations in England at the time. The book contains 9 chapters, each exploring a sexual deviation or potential influences. It is largely composed of case studies and directly quotes the individuals he examined, providing the raw descriptions and perspectives of the individuals, rather than his own version of their deviations. Source: Wikipedia (en)