With what has Tesla put humanity in his debt?

With what, in fact, has Tesla put humanity so greatly in his debt? The English professor R. Kapp, in his lecture on the occasion of the centenary of Nikola Tesla’s birth, answered this question in a very graphic way:

“Far back in prehistory an anonymous genius invented the wheel. That was one of the most useful things a man has ever given to his race. This invention was perhaps quite obvious; but the invention of an invisible wheel, made of nothing other than a magnetic field, was far from obvious, and that is what we owe to Tesla. It could have arisen only in one brilliant and unique intellect.”