Our job enabled us to take many foreign friends on tours in China. During such tours they asked a lot of questions, such as why the Chinese eat dumplings, post portraits of the Gate Guardian God on their doors and let off firecrackers on New Year's Day.

Why should the tiles that cover roofs in Beijing come in yellow, green or black? What do the animal figurines that perch on roof ridges symbolize? Why the stone turtles are burdened with stone tablets? What's the purpose of the ceremonial columns in front of Tian'anmen Gate? Twenty years ago, a French friend told us that during his travel in China be was keenly on traditional Chinese culture but found it difficult to understand. He suggested that we write a book on Chinese culture.