James Clerk Maxwell was a Scottish physicist and mathematician who made significant contributions to the field of electromagnetism. He is best known for his development of the classical theory of electromagnetic radiation, which led to the prediction of the existence of electromagnetic waves. This was a major breakthrough in the understanding of light and other forms of radiation, and it laid the groundwork for many of the technologies we use today, such as radio, television, and wireless communication. Maxwell's work also had a major influence on the development of modern physics, and he is considered one of the greatest scientists of all time.