Author, critic, activist, philosopher, humanist: Susan Sontag was one of America’s most influential intellectuals. Though she published dozens of books, plays, monographs, and films on a vast variety of topics, from photography to AIDS to communism, she thought of herself as a student all her life. In her journals, Sontag recorded her thoughts, notes on her works in progress, and fragments from her voracious reading. This note from October 1973 reads like an instruction to herself. When the whole world is out there, just waiting to be studied, one mustn’t hesitate.