Ludvig Valentin Lorenz (1829-1891) was Denmark's first theoretical physicist of international recognition. Although generally considered a secondary figure in the history of science, he contributed importantly to a wide range of subjects ranging from materials science to fundamental theories of optics and electrodynamics. Apart from his theoretical work he was also a brilliant experimenter who felt as much at home in his laboratory as behind his desk. Today his name is eponymously associated with terms such as the Lorenz gauge, the Lorenz-Lorentz formula, the Lorenz-Mie theory and the Lorenz number.