Theodor Theodorsen was a Norwegian engineer and physicist, known for his significant contributions to the field of fluid dynamics. He is particularly recognized for developing the Theodorsen function, which is essential in the study of oscillating airfoils and has applications in aerodynamics. Born in 1893, Theodorsen's work laid the groundwork for understanding how air interacts with moving surfaces, such as wings. His research has influenced various areas, including aerospace engineering and hydrodynamics, making him a notable figure in the advancement of engineering sciences.