A gripping story of invention and innovation in the 19th century. Two things particularly struck me: (a) that the initial experiments with the electric telegraph were much earlier than I had imagined and well before Faraday's theory of electricity explained what lay behind it all; (b) the long, 30 year, gestation then the incredible explosion of take up of the telegraph (650,000 miles of cable in just a few years) and the pace (within a decade) within which the key undersea cables were laid. Breathless stuff.