On Sept. 14, 1822, as legend tells the tale, Jean-François Champollion burst into his brother's Paris office at the Academy of Inscriptions and Belles-Lettres, flung a bundle of drawings upon the desk and cried, "Je tiens mon affaire!" ("I've done it!"). Champollion promptly fainted before he could utter news of the great intellectual feat for which he is still celebrated: the decipherment of ancient Egyptian hieroglyphs. The story of the young, frail, hotheaded scholar and his volatile time, full of upheavals political and scientific, is a remarkable tale, wonderfully told in Andrew Robinson's...