  At the beginning of the 20th century the classical electron theory (or,
perhaps more appropriately, the classical electromagnetic mass theory) - the
first physical theory that dared ask the question of what inertia and mass were
- was gaining momentum and there were hopes that physics would be finally able
to explain their origin. It is argued in this paper that if that promising
research path had not been inexplicably abandoned after the advent of
relativity and quantum mechanics, the contemporary physics would have revealed
not only the nature of inertia, mass, and gravitation, but most importantly
would have outlined the ways of their manipulation. Another goal of the paper
is to try to stimulate the search for the mechanism responsible for inertia and
gravitation by outlining a research direction, which demonstrates that the
classical electromagnetic mass theory in conjunction with the principle of
equivalence offers such a mechanism.
