  An account is given of an interesting but unknown theory by Majorana
regarding scalar quantum electrodynamics, elaborated several years before the
known Pauli-Weisskopf theory. Theoretical calculations and their interpretation
are given in detail, together with a general historical discussion of the main
steps towards the building of a quantum field theory for electrodynamics. A
possible peculiar application to nuclear constitution, as conceived around
1930, considered by Majorana is as well discussed.
