This paper read in Cologne a few months before he died expanded relativity into geometrical form. This separate form of the paper was printed as a tribute after his sudden and tragic death. Minkowski here introduces the idea that made possible the expansion of the Special Relativity of 1905 into the General Relativity of 1916. By making time a dimension equivalent to the three spatial dimensions, Minkowski made it possible to handle transformations in space and time in an entirely new way.