As the title suggests, this is a book that may be read from left to right or from right to left, giving it a mirrored structure. Among approximately six hundred thousand anonymous pictures in his collection, Cai Dongdong catalogues them by period, by the costume and make-up of the sitters, and by the notes written on the back. He then pairs portraits of women of similar age, facial structure and posture from two different historical periods, before and after the founding of the People's Republic: on the right-hand page the years of the Republic of China, on the left the years after.