John Derbyshire (born June 3, 1945) is a British-American writer, commentator, and mathematician. He is known for his conservative columns in National Review and his popular mathematics book Prime Obsession. Derbyshire's work spans politics, culture, mathematics, and history, often stirring controversy. Born in England, he later moved to the United States and became a U.S. citizen. His writing style is sharp and challenges mainstream views, especially on race and immigration.