I have not seen this new edition, but I read the original work in the mid eighties and it made a considerable impression on me.
The basic thrust of the book, as I recall it, is that emotional processes are at root rational processes that can be understood and manipulated (influenced might be a better word) with examples taken from theater, poetry etc. The book also offers some insight into Aristotle's world view that left me with a deep respect for his thinking.
While I am not qualified to judge the book's academic merits, I found it to be cogent, thought-provoking and a refreshing change from the then current vogue of confounding emotionality and irrationality (a persistant confusion even today). I give an unreserved recommendation to anyone looking to understand what emotions are and how they may be managed. I would also recommend it to anyone interested in ancient Greek civilization in general even though it touches a very thin slice of that pie. Students and scholars of Aristotle and philosopy will make their own judgements, of course.