"Clerk Maxwell's Theory of Electromagnetism" is a classic research work written by the outstanding physicist Hendrik Lorentz. In this book, the author examines in detail the main provisions of James Clerk Maxwell's theory of electromagnetism, which changed the world of physics. Some of these provisions were discovered by Lorentz, and by the way, it was he who first introduced the terms "electron" and "concentrated system". The author examines electric and magnetic phenomena in detail, and also illuminates important connections between them, which opened new horizons in the development of physics. Lorentz's book is an important source for understanding the foundations of modern physics and is considered a classic in the field of electrodynamics.