Debby Applegate is an American historian and biographer. She is the author of The Most Famous Man in America: The Biography of Henry Ward Beecher, for which she won the 2007 Pulitzer Prize for Biography or Autobiography.
Born in Eugene, Oregon, Applegate attended Amherst College as an undergraduate, where she began a two-decade fascination with famous alumnus Henry Ward Beecher, a 19th-century abolitionist minister who was later the subject of a widely publicized sex scandal. She made Beecher the subject of her dissertation in American Studies at Yale, where she received a Ph.D. After several more years of research, Applegate published The Most Famous Man in America, which was praised by critics and awarded the Pulitzer Prize. She has announced that her second book will be a biography of New York City brothel-keeper Polly Adler.