In the beginning of the book, Tolle recalls who he was as a man in his late 20s. He was unhappy with his life and constantly had suicidal thoughts. I think this excerpt from the book is probably the best way to convince you that Tolle's concepts hold weight:

"I cannot live with myself any longer." This was the thought that kept repeating itself in my mind. Then suddenly I became aware of what a peculiar thought it was. "Am I one or two? If I cannot live with myself, there must be two of me: the 'I' and the 'self' that 'I' cannot live with."

"Maybe," I thought, "only one of them is real."

I was so stunned by this strange realization that my mind stopped. I was fully conscious, but there were no more thoughts. Then I felt drawn into what seemed like a vortex of energy. It was a slow movement at first and then accelerated. I was gripped by an intense fear, and my body started to shake. I heard the words "resist nothing," as if spoken inside my chest. I could feel myself being sucked into a void. It felt as if the void was inside myself rather than outside. Suddenly, there was no more fear, and I let myself fall into that void. I have no recollection of what happened after that.

I was awakened by the chirping of a bird outside the window. I had never heard such a sound before. My eyes were still closed, and I saw the image of a precious diamond. Yes, if a diamond could make a sound, this is what it would be like. I opened my eyes. The first light of dawn was filtering through the curtains. Without any thought, I felt, I knew, that there is infinitely more to light than we realize. That soft luminosity filtering through the curtains was love itself. Tears came into my eyes. I got up and walked around the room. I recognized the room, and yet I knew that I had never truly seen it before. Everything was fresh and pristine, as if it had just come into existence. I picked up things, a pencil, an empty bottle, marveling at the beauty and aliveness of it all.

That day I walked around the city in utter amazement at the miracle of life on earth, as if I had just been born into this world.