The First hundred years of the Royal Aeronautical Society have seen nearly all of man's significant achievements in controlled flight by airships, aeroplanes and helicopters. This is hardly surprising, since the Society was formed in 1866, when the time was nearly ripe for such developments to begin. It is perhaps even more striking, however, to realise that throughout the second half of the same century, most of the early evolution of an even more ambitious form of flight has also taken place.