Theodore Mook (born February 26, 1953, Mount Kisco, New York) is an American cellist who has played in more than 1,000 Broadway performances in New York City, produced records, played on motion picture soundtracks and, along with Ezra Sims, invented computer fonts used in microtonal music composition. He is best known for his interest and contributions to microtonality music. After moving to Charlestown, Rhode Island, Mook played alongside Grammy-winning artist Eugene Friesen.