In the winter of 1950, Margaret Sanger, then 71, and who had campaigned for women's right to control their own fertility for five decades, arrived at a Park Avenue apartment building. She had come to meet a visionary scientist with a dubious reputation more than 20 years her junior. His name was Gregory Pincus. In 'The Birth of the Pill', Jonathan Eig tells the extraordinary story of how, prompted by Sanger, and then funded by the wealthy widow and philanthropist Katharine McCormick, Pincus invented a drug that would stop women ovulating. With the support of John Rock, a charismatic and, crucially, Catholic doctor from Boston, who battled his own church in the effort to win public approval for the controversial new drug, he succeeded. Together, these four determined men and women changed the world. Spanning the years from Sanger's heady Greenwich Village days in the early 20th century to trial tests in Puerto Rico in the 1950s to the cusp of the sexual revolution in the 1960s, this is a grand story of radical feminism, scientific ingenuity, establishment opposition, and, ultimately, a sea change in social attitudes.