Power of Now by Eckhart Tolle pg. 15

…You can take the first step right now. Start listening to the voice in your head as often as you can. Pay particular attention to any repetitive thought patterns, those old gramophone records that have been playing in your head perhaps for many years. This is what I mean by "watching the thinker," which is another way of saying: listen to the voice in your head, be there as witnessing presence…listen to it impartially…do not judge or condemn what you hear...You'll soon realize: there is the voice, and here I am listening to it, watching it. This `I am' realization, this sense of your own presence, is not a thought. It arises from beyond the mind…"