With glitzy nightclubs, saunas, karaoke lounges and brothels, Hong Kong's sex business is booming. But how do local prostitutes compete with an endless supply of girls from China? To find out, Yang spent a year with the city's hookers. The result is an eye-opening book which shows the human side of sex for sale - easy money, financial ruin and hopeless relationships - and first-hand insights into the huge but hidden sex industry.