1) The Power of Kabbalah by Yehuda Berg
2) The Power of Now by Eckhart Tolle
3) Conversations with God by Neale Donald Walsch (Series)
4) The Messenger by Klaus Joehle
(I have found the last 3 online for free. Perhaps you can find the first one for free as well!)
I’ve read a bunch of other books, but none of them improved my life like these four. I have actually listed them in order of how I read them. The first one was given to me by a friend and it opened my eyes to spirituality. The night after reading it, I felt my chakras being balanced. I kid you not! Found lots of recommendations for the second book and they were all correct—it’s phenomenal. The third book is actually a series of 3 books and I stumbled upon the first one on StumbleUpon! Found the rest of the series online for free too and it was amazing. And finally, I heard a meditation by the author of the 4th book and I loved it! So, I found his book and loved it even more! Before these books, I was a completely different person. I love them all! Even though it’s not a book, I’d also recommend listening to videos by Abraham Hicks (they are also life changing).
Power of Now is pretty amazing. Life-changing stuff imo. Highly recommended.