You can learn a lot about nonduality and awakening by reading books. There are many excellent books to help guide you.
However, it is extremely rare to realize your true nature simply by reading a book, or even several books. In fact, I've never come across a person who claimed that a book -- and nothing more -- led to an abiding self-realization. In many instances, a book may trigger an intense interest in self-inquiry, and it may provide a powerful glimpse of truth about one's true nature.
But a book, even one written by a self-realized master, will not lead to a clear understanding of the nondual reality. Many of us have had the experience of reading a review on Amazon or some other website, telling us "this is the last nonduality book you'll ever need" -- as if reading that book will offer us the complete nondual recognition and answer all our questions about reality.
It always ends in disappointment. The book doesn't deliver what we want.
That being said, nonduality books can be quite valuable. The vast majority of those who are attracted to nonduality read LOTS of books on the subject of nonduality, enlightenment, or awakening. I think it's fair to say many seekers become addicted to reading books on nonduality. It's not the worst addiction you could have.
I've been a nonduality book junkie for a while, although the habit was much more intense a few years ago. I read nonduality books because I love these wonderful, unique expressions of the nature of Reality. I feel more relaxed, more peaceful, and more loving as I read nondual books and materials. There's something in them that touches me deeply. And I appreciate the varied ways in which Truth is expressed. There is simply a joy in reading the beautiful expressions of Truth that come from those who have realized their true nature.
The trap many seekers fall into is this: they think that the next book they read will give them the nondual recognition. They believe the book CAN induce that abiding self-realization they crave. They read the book and it doesn't trigger the immediate awakening they hoped for. So, they get another book....and another book...and another 12 books...and still, they haven't "gotten" what they're seeking.
They're chasing a state that they think is not accessible to them right now. They think enlightenment is a state of continuing peace and bliss. I used to do the same thing. It's hard for a seeker to avoid this trap at the outset. The mind latches onto the idea that enlightenment is just around the corner, to be found in the next book, the next video, or the next satsang.
The mind/ego believes that enlightenment is not here now, but can be achieved as a goal in the future. This search leaves us frustrated, until we see the error of our ways and STOP.
I still enjoy reading nonduality books, but I no longer read them in the hope that the book will miraculously produce my awakening. I read them for the pure peace and enjoyment of reading about Truth. I don't expect to get anything from these books.
So, if you are one of those who reads nonduality books, consider WHY you read them. If they touch you and resonate with you, enjoy reading these materials. Read for the joy of drinking in these beautiful expressions of your true nature.
However, if you are looking to get something from them, or hoping to accelerate your realization or understanding by learning some new technique or information, consider that you may be moving off course.
Better to relax and simply BE.