  An analysis of the work of Mira Fernandes on unitary theories is presented.
First it is briefly mentioned the Portuguese scientific context of the 1920s. A
short analysis of the extension of Riemann geometries to new generalized
geometries with new affine connections, such as those of Weyl and Cartan, is
given. Based on these new geometries, the unitary theories of the gravitational
and electromagnetic fields, proposed by Weyl, Eddington, Einstein, and others
are then explained. Finally, the book and one paper on connections and two
papers on unitary theories, all written by Mira Fernandes, are analyzed and put
in context.
