Debby Applegate is an American historian and biographer. She is the author of Madam: The Biography of Polly Adler, Icon of the Jazz Age and The Most Famous Man in America: The Biography of Henry Ward Beecher, for which she won the 2007 Pulitzer Prize for Biography or Autobiography.

Henry Ward Beecher was an American Congregationalist clergyman, social reformer, and speaker, known for his support of the abolition of slavery, his emphasis on God's love, and his 1875 adultery trial. His rhetorical focus on Christ's love has influenced mainstream Christianity through the 21st century.