Foreword by the Associate Editor [Historical Corner]

In a few years it will be the 150th anniversary of the fundamental paper by J.C. Maxwell, “A Dynamical Theory of the Electromagnetic Field” [1], reporting an account of the speech he gave on December 8, 1894, at the Royal Society (Figure 1). In that fundamental paper, Maxwell introduced eight equations in Cartesian coordinates, containing the differential relations among the electrical and magnetic fields. These relations unified electricity, magnetism, and light, which were until then separate realms of physics (Figure 2). These equations, with their corresponding modern versions, are reported in Figures 3 to 8.