As a boy I made little wireless sets out of tin cigarette boxes with a receiving coil wound in such a way that it was on the right wavelength for Radio Luxembourg. The ethereal sound of 1950s pop music in the earpiece was spellbinding. How that signal got to me, I did not bother to ask: the thrill of receiving it was enough. Today, as millions chatter away on their mobile phones, I fear that thrill is gone; the astonishing achievement of harnessing invisible, inaudible electromagnetic waves to send messages of all kinds is taken for granted. And the once-famous man who first showed how it could be done is now all but forgotten.