In 1965, Helen Gurley Brown, author of the groundbreaking bestseller Sex and the Single Girl, took over an ailing Cosmopolitan and soon revamped it into one of the most bankable—and revolutionary—brands on the planet. At a time when women’s magazines taught housewives how to make the perfect casserole, Helen spoke directly to the single girl next door, cheekily advising her on how to pursue men, money, power, pleasure, and, most of all, personal happiness. In this retro romp that will appeal to fans of Mad Men, journalist Brooke Hauser reveals how a self-proclaimed “mouseburger” from the Ozarks became one of the most influential women of her time. Though she was married (to the renowned movie producer David Brown), no one embodied the idea of the Cosmo Girl more than Helen, who willed, worked, and flirted her way to the top. Bringing New York City vibrantly to life during the sexual revolution and the women’s movement, and featuring a rich cast of characters, including Hugh Hefner and Gloria Steinem, Enter Helen is the riveting story of a polarizing pioneer who bucked convention to define her own destiny, baiting a generation that both revered and rejected her.