Jill Lepore's "Book of Ages: The Life and Opinions of Jane Franklin," a biography of Ben Franklin's sister, comes out this fall. This week in the magazine, Lepore writes about her decades-long interest in the subject, how the story figured into her relationship with her own mother, and what finally motivated her to overcome her reluctance and write the biography. Judith Thurman is also a biographer, with books about Isak Dinesen and Sidonie-Gabrielle Colette. Here, Thurman and Lepore talk with Sasha Weiss about Jane Franklin, what motherhood has forced different generations of women to give up, and the history of American women writers. Also, writer Ruth Franklin on the sixtieth anniversary of Shirley Jackson's classic tale, "The Lottery."