?tienne-Louis Malus (1775-1812) was a French officer, engineer, physicist, and mathematician. He participated in Napoleon's expedition into Egypt (1798 to 1801) and was a member of the mathematics section of the Institut d'?gypte. His mathematical work was almost entirely concerned with the study of light. He conducted experiments to verify Christiaan Huygens' theories of light and rewrote the theory in analytical form. His discovery of the polarization of light by reflection was published in 1809 and his theory of double refraction of light in crystals, in 1810. Malus is probably best remembered for Malus' law, giving the resultant intensity, when a polarizer is placed in the path of an incident beam. His name is one of the 72 names inscribed on the Eiffel tower. He died in 1812 of phthisis (disease characterized by the wasting away or atrophy of the body or a part of the body, tuberculosis of the lungs) at the age of 37.