Henry Martyn Robert (May 2, 1837 – May 11, 1923) was the author of Robert's Rules of Order, which became the most widely used manual of parliamentary procedure and remains today the most common parliamentary authority in the United States. Under command of Silas Casey during the Pig War he built the fortifications on San Juan Island. In the American Civil War, he was assigned to the Corps of Engineers and worked on the defenses of Washington, D.C., Philadelphia, and several New England ports. He died in Hornell, New York, and is buried at Arlington National Cemetery.