How many editions are they available for this Chen taiji classic, Illustrated Canon of Chen Family Taijiquan 陈氏太极拳图说 by Chen Xin (陈鑫) Quite a lot apparently.  Here are 5. I think the best quality is the one that has 4 volumes (the dark blue cover set ).
The Illustrated Canon of Chen Family Taijiquan was written by Chen Xin from 1908. In 1919, the manuscript was sent off to Nanjing to try to get it published. That did not work out and the manuscript was lost.  in 1929, at his deathbed, …

Just when I thought all about Chen taiji have been written (at least the chinese books), I saw a few new books on the shelves when I visited the bookstores recently.  I usually try to buy them as they are relatively affordable compared to English books and their printing quality has improved a lot over the past few years.
One of the new book is by Ma Hong, titled 陈式太极拳劲道释秘-拆拳讲劲 . Roughly translated as Chen Style Taijiquan Secrets Explained – Dissecting the Routine to Explain the Jing.
I have not read it but …

Finally someone by the name of Alex Golstein translated the Chen Taiji classic 陈氏太极拳图说 by Chen Xin (陈鑫）.  This book is quoted in almost all Chen Style TaijiQuan books. It was a delight finding this book in the bookstore.However this book is written in classical Chinese with no punctuation marks. It is not easy to understand if even if you know Chinese. The topics that he covered are YingYang Theory, silk reeling theory, meridian theory and notes on the various postures. 
Now with the English translation, non Chinese readers may attempt …