Since Darwin's day, we've been told that sexual monogamy comes naturally to our species. But this narrative is collapsing. Here, renegade thinkers Christopher Ryan and Cacilda Jethá, while debunking almost everything we "know" about sex, offer a bold alternative explanation. Ryan and Jethá's central contention is that human beings evolved in egalitarian groups that shared food, child care, and, often, sexual partners. Weaving together convergent,...

"In the summer of 1974, in a derelict Rhode Island mansion called Trevor Hall, a team of scientists taught American Sign Language to a chimpanzee. They affectionately christened their subject "Smithy." His official name was Webster. The Smithy Project ended in tragedy, some believing that a dark presence inside Trevor Hall had been disturbed. Webster was acquired by CSAM, a research lab in California run by the iron-fisted Manfried Teague. CSAM had...