Lemuel K. Washburn was a prominent American author, editor, and lecturer in the late 19th and early 20th centuries. A leading figure in the American Freethought movement, he dedicated his life to promoting reason, secularism, and scientific inquiry over religious dogma. He served as the final editor of the long-running freethought journal, the Boston Investigator, and authored several influential books and pamphlets challenging religious orthodoxy. Washburn's work remains an important part of the history of American secularism and rationalism.