A visitor is attracted by electronic books at the 23rd Hong Kong Book Fair in Hong Kong, south China, July 18, 2012. The seven-day Hong Kong Book Fair opened at the Hong Kong Convention and Exhibition Center on Wednesday, attracting more than 530 exhibitors from 23 countries and regions. [Xinhua/Lui Siu Wai]

A citizen experiences a "Face Recognition Device", which can automatically recommend books to readers by identifying their face characteristics, at the 23rd Hong Kong Book Fair in Hong Kong, south China, July 18, 2012. The seven-day Hong Kong Book Fair opened at the Hong Kong Convention and Exhibition Center on Wednesday, attracting more than 530 exhibitors from 23 countries and regions. [Xinhua/Lui Siu Wai]