The notable scientist who developed the theory of electromagnetism is James Clerk Maxwell. In the mid-19th century, Maxwell formulated a set of equations, known as Maxwell's Equations, that describe how electric and magnetic fields interact and propagate through space. His groundbreaking work unified previously separate theories of electricity and magnetism, providing a comprehensive framework for understanding electromagnetic phenomena. Maxwell’s contributions laid the groundwork for various modern technologies, including radio and telecommunications. His influence extends beyond physics, impacting fields like engineering and even influencing Albert Einstein's theories.