Is it sinful to read them just for historical information?
What if their name is not included in the index of prohibbited books?

For example if the book is about women's spirituality in the whole history and has one or two section about catholic women; do I sin if I read those sections?

The book I want to buy, is a historical one, it is not about the church or faith per se. I really want to read it because this book, focuses on people's ways of mysticism not on how God gave them the grace.
There is something about catholic books: They so focus on Jesus and His grace, that they forget to write about other people's actions, thoughts and reactions. It is like when sun shines and stars cannot be seen. So if you want to study a star, you must look at it when sun (The Son) is abscent.
It is why I want to read a book written by a secular author.

The forbidden movie and book lists are basically non-existent now, thanks to the fact that we lack shepherds, but have a vast amount of hirelings that don't care about the salvation of souls.

Best things to do, imo, is to stick with Catholic authors, that have a good reputation, pre-conciliar or Traditional Catholic.

"There is something about catholic books: They so focus on Jesus and His grace, that they forget to write about other people's actions, thoughts and reactions."

This is a really good point.  Secular literature has thrived the way it has because too often Catholic literature is abstract and mystical, and I am not sure that mystical experience can really be shared or put into words on a page in a way that is satisfying for the reader.  Mystical experience has to be EXPERIENCED.   Not that Catholics shouldn't write mystical books, or that they shouldn't be a fundamental part of our diet -- just not the whole diet.  

Humans thirst to share their concrete, real experiences with other humans.  This is why my favorite Catholic author is Augustine, because we know his struggles with the world and can relate to him.  To me he stands head-and-shoulders above any other Catholic writer, even if the idea of the "Confessions" has gotten me in trouble when taken too far.  I also feel Jean Gerson perfectly reconciled the down-to-Earth and mystical elements of Christianity, from what I know about him, though I don't have his works.  

I often feel curiously empty after reading something like Bonaventure's Journey of the Mind to God with its visions of six-winged angels.  It just doesn't do anything for me.  I'll see six-winged angels in heaven, if I get there.  I want someone to tell me how they conquered sin, how they came to God, their mistakes even after coming to God, their fights with heretics, etc., placing it in a precise historical context that makes their world come alive.  

The problem is that very few of us appreciate, while we're here, that the mundane details of our everyday lives may one day become very interesting.  But I don't think there will be an Augustine in our time.  Our world today is truly alien and fantastic and no book today could contain all of its contradictions and disasters except the book written by God.

  So is it sinful or not?

 Thank you!
BTW, who is the man in your signature? I don't know why, but he looks very familiar!