China is a big country and its cookery is one of the world's greatest. In the last century all nations everywhere have been introduced to its tastes, flavours and cooking methods. But an understanding of Chinese food history is hard to come by: the country is large and the history is long. Hsiang Ju Lin has interrogated the written record, some of it dating back to the 5th century BC, and most recently from books current in the People's Republic today;...