Theodor Franz Eduard Kaluza (9.02.1885—19.02.1954) was a German theoretical physicist. He was born in Ratibor (now Racibórz, in the Polish People's Republic). He graduated from the University of Königsberg, where he worked from 1909. In 1929 —35 he was professor at the University of Kiel, and from 1935 at the University of Göttingen.
His research concerned general relativity, the theory of gravitation, mathematical physics and nuclear models. In unified field theory he proposed (1921) the so-called five-dimensional approach, introducing a five-dimensional manifold intended to replace four-dimensional space-time and endowing it with a five-dimensional metric (Kaluza's five-dimensional theory). Four of the dimensions were to be space-like and the fifth time-like. To reproduce the observed four-dimensionality of space-time he postulated the congruence of the space-like curves: only one curve could pass through each point of his manifold. The Brans — Dicke scalar-tensor theory of gravitation is a generalisation of Kaluza's theory.