I bought a copy of "Primordial Pugilism ( T'ai Chi Ch'uan ) in the early 1980s. It was published in 1976 and written by Tseng Ju-Pai ( Chiu Yien ).
The reason I bought it was because of the fold out charts with pictures of Yang Chengfu, Chen Wei Ming and the author in postures form the Yang long form. It also has a chapter detailing applications to the form. It's interesting to contrast the earlier pictures of Yang Chengfu in the white top with his later, more well known photos.
I love looking at old photographs of tai chi practitioners.