In the spring of 1906, Nobel laureate H.A. Lorentz gave a famous series of lectures at Columbia University. Gathered in one volume and published as The Theory of Electrons in 1909, these talks are still widely read and admired today, more than 100 years later. This collection includes lectures on:rn rn . the theory of free electronsrn . the emission and absorption of heatrn . the theory of the Zeeman-effectrn . the propagation of light in a body composed of moleculesrn . the theory of the inverse Zeeman-effectrn . the optical phenomena in moving bodiesrn rn Extensive notes, complete with mathematical equations, complement the text, and an extensive index will aid the reader.rn rn Dutch physicist HENDRIK ANTOON LORENTZ (1853-1928) shared the Nobel Prize in physics with Pieter Zeeman in 1902. His publications include The Einstein Theory of Relativity: A Concise Statement (1920), Lectures on Theoretical Physics (1927), and Problems of Modern Physics (1927).