In 1962, Brown's book "Sex and the Single Girl" was published in 28 countries, and stayed on the bestseller lists for over a year. In 1964 the book inspired the film of the same name starring Natalie Wood. In 1965, Brown became editor-in-chief of "Cosmopolitan", then a literary magazine famed for high-toned content, and reinvented it as a magazine for the modern single career-woman. In the 1960s, Brown was an outspoken advocate of women's sexual freedom and sought to provide women with role models in her magazine. She claimed that women could have it all – "love, sex, and money". As a result of her advocacy, glamorous, fashion-focused women were sometimes called "Cosmo Girls". Her work played a part in what is often called the sexual revolution.