You are reading these words. That is easy to know. It is harder to notice.
Try it now. While your eyes move along this line, let part of your attention turn back toward the one who is reading. Notice how you are sitting. Notice your breath. Notice the voice in your head that says these words as you read them.
Something just changed. A moment ago there was only the page. Now there is the page and you. Your attention has split in two: half on the words, half on yourself.
That small split is where this whole book begins. Most of the day, attention pours out in one direction. It goes into the phone, the conversation, the worry, and nothing is left for the one doing it. The tradition of Gnosis calls this being asleep. It calls the split you just made the beginning of waking up.
You do not need to believe anything to try this. You only need to do it and see what you notice. Everything in these hundred pages is meant to be tested that way: by you, in your own day.