A book about human soul

Dear Rabbi! Is it permitted to read a book about human soul that was written by a gentile? People who read this book recommended it to me and said that it doesn’t promote any kind of specific worldview, and that there are no problems with this book at all. Thank you very much!  

Dear …!

Any book about a human soul will always contain certain opinions and a certain worldview. All schools of psychology promulgate their respective outlooks, and almost all of them, at least to a certain extent, will deny freedom of choice and other basic tenets of Judaism. When a book seems innocent and devoid of particular outlook — that’s when it could be the most dangerous, because it will sneak in foreign ideas through the back door, and influence your subconscious, without your noticing it and trying to defend yourself against these views.

If there is a specific strictly-defined knowledge that you want to gain by reading this book, for example, you want to learn how to treat autism, then you should turn to a knowledgeable rabbi. You should ask him, whether reading such a book is justified in your case, and whether you can be sure of yourself, that you’ll be able to separate the wheat from the chaff. It’s impossible to give a generalized answer to such a question.

Tractate Sotah 49b