No cloistered don, this tall, married Englishman was a freethinking intellectual. A nudist, he was devoted to quirky folk dancing. In 1937, while working as a biochemist at Cambridge, he fell in love with a visiting Chinese student, with whom he began a lifelong affair. His mistress persuaded him to travel to her home country, where he embarked on a series of expeditions to the frontiers of the ancient empire. He searched for evidence to bolster a conviction that the Chinese were responsible for hundreds of humankind's most familiar innovations—including printing, the compass, explosives, suspension bridges, even toilet paper—often centuries before others. His journeys took him across war-torn China, consolidating his admiration for the Chinese.