Wow. Okay, let's start with: Shakespeare, since I was still in grade school when I worked my way through most (I disliked some of the history plays) of his plays in a huge book my parents had on the living room shelf. I worked my way through most of their Encyclopedia Brittanica books too, but they were just factual. Old Will taught me how to hold the reader's interest. I wanted to know how adults thought, what they valued, and I learned a whole lot by reading all of those royalty plays (crowns), comedies (clowns) and tragedies (corpses).
At various times in my college days I was enthralled with Jean Paul Sartre's No Exit, for his Existentialism, and George Bernard Shaw for his plays full of insights on human nature. At that time I also began reading Anne Rice's vampire books, and the one that has stuck with me the longest is Lestat. When Lestat brings his elderly mother across, he's horrified that she wants to head off alone into the woods, but she points out to him that for the first time ever, she doesn't have to fear what any man could do to her, so she's going to live her life HER way from now on. A wet dream for most women, no? But before she leaves they discuss what immortality means. If you live forever, would you improve, to become a better person? Or would you just become more of what you were like in your mortal days? So if you were a pompous jerk, would you grow to be a better humanitarian, or become an even bigger pompous jerk?
Then there are the various books by Desmond Morris, the zoologist who writes about man as a species, as if he was an alien studying us. The Naked Ape is his first, followed by The Human Zoo, with Intimacy next. All of these books examine human behavior in minutia, and I love the insights I've felt as I read them. In the same vein, The Ape That Spoke by John McCrone talks about memory. He explains it as a series of threads that link what we know to what we're seeing and allow us to make sense of our surroundings. He also says memory is based on words, which I've said for years--that's why we don't remember our own babyhood...we didn't have words yet to tie the images in our heads.
The most recent book I've read that changed my thinking is Static, by L.A.Witt. This book won the EPIC award for Sci-Fi in 2013. It makes you question gender and love on a most basic level. I laughed in some parts and cried in others. The book became a part of me so much that I'm still thinking about its ideas months after reading it, and I gave copies to friends/relatives as gifts to share it with them and support the author.
What about you? What books have changed you mentally?