In 1956, a garbage man living in the Kowloon neighborhood of Hong Kong, having reached the Dantean age of thirty-five, declared himself emperor. Tsang Tsou-choi grandly dismissed the powers that have made claims on Hong Kong—the Qing Dynasty in the nineteenth century, the British in the twentieth, Communist China in the twenty-first—and said (much to the alarm of his wife and children) that it had belonged by right to his ancestors and now belonged to him. Graffiti was the eccentric means by which...