This is the Standard of Perfection, It not only contains the "standard" or detailed description for each breed, but the first 40-50 pages are absolutely the encyclopedia of the chicken and these pages alone are worth the price of the Standard.
This is the hardcopy version, because I prefer hard bound books, but there are inexpensive spiral bound versions sold by the APA as well. Beware of Ebay sellers and internet sellers of "fake" versions. The book can only be purchased from the APA.
I just ordered my copy. One thing is for sure...become a chicken enthusiast results in a lot of new reading material.