High Quality Content by WIKIPEDIA articles! The theory of special relativity plays an important role in the modern theory of classical electromagnetism. First of all, it gives formulas for how electromagnetic objects, in particular the electric and magnetic fields, are altered under a Lorentz transformation from one inertial frame of reference to another. Second of all, it sheds light on the relationship between electricity and magnetism, for example showing that an electric force in one frame of reference may be a magnetic force in another and vice-versa, and likewise that certain laws of magnetism can be "derived" from corresponding laws of electricity and vice-versa. Third, it motivates a compact and convenient notation for the laws of electromagnetism, namely the "manifestly covariant" tensor form.