Although I gave it a low rating, this book presented me with information that personally was enlightening. It helped me a lot with its premises and logic. I'll explain.
The writing of the book is amazing, although a bit difficult because it's old.
Despite such positivities, one negativity is that the book doesn't have an obvious claim. Is the author claiming that what he calls Excitation is capable of solving each and every kind of suffering? Such a claim would absolutely fail under the lights of modern psychology.
However; the book could also be *merely* claiming that Inhibition (the opposite of Excitation) should be considered as a factor when dealing with inobvious, confusing medical cases. Such a claim is absolutely much more digestable than the former. As far as I know; Inhibition, in the modern psychological literature, is known to cause unexplainable symptoms. And the arguments presented in this book are enough in my opinion, as a dummy who knows nothing about medicine, to prove, or make a case for such a claim.
I also like the arguments he used to criticize psychoanalysis. It's very true that they construct extremely abstract building blocks that happen to be unfalsifiable, just to keep arguing about their form for the entirety of their careers. It gave me an insight on economics: when we use math in economics, we account for the inefficiency of language, which could be very wise. However, my knowledge in economics is too limited to make an assertive comment. But what I'm pointing at is - ignoring the qualitative nature of psychology just for the sake of argument - that if psychoanalysts were to describe their theories using mathematical models, their fallacies would have been very obvious.
Finally, I like the author's emphasis on the hidden magic that spontaneity has. It's better for readers to also learn about the 3rd wave of behaviorism to find out how they can actually use spontaneity, but it's unnecessary. Freestyle rappers - the kings of spontaneity - don't go around flipping pages of each and every psychology book out there, after all.