  We discuss a previously unpublished description of electromagnetism outlined
by Richard P. Feynman in the 1960s in five handwritten pages, recently
uncovered among his papers, and partly developed in later lectures. Though
similar to the existing approaches deriving electromagnetism from special
relativity, the present one extends a long way towards the derivation of
Maxwell's equations with minimal physical assumptions. In particular, without
postulating Coulomb's law, homogeneous Maxwell's equations are written down by
following a route different from the standard one, i.e. first introducing
electromagnetic potentials in order to write down a relativistic invariant
action, which is just the inverse approach to the usual one. Also, Feynman's
derivation of the Lorentz force exclusively follows from its linearity in the
charge velocity and from relativistic invariance. Going further, i.e. adding
the inhomogeneous Maxwell's equations, requires some more physical input, and
can be done by just following conventional lines, hence this task was not
pursued here. Despite its incompleteness, this way of proceeding is of great
historical and epistemological significance. We also comment about its possible
relevance to didactics, as an interesting supplement to usual treatments.
