What kind of world do you live in? A world of solid ground with people and trees, oceans with clouds above it and, higher still, the enormous emptiness of space? Are you one of the billions of people in that world? If you answer "yes" to those questions, then you are mistaken! If you were able to answer "yes" to them, then that means that throughout the course of your life you have probably ignored a most important truth. The fact is, you do not live in the kind of world described above at all. In your world, there is no distance of even a few meters, let alone of billions of kilometers or galaxies light years away. Actually you live in a very small enclosed space—in a tiny, locked room at the top of a giant tower. You have never left that room. You have never stepped outside it or been anywhere else. All you have seen are different shapes, people and spaces reflected on the walls of that room. You have heard only the sounds emitted from loudspeakers concealed in there. In fact, in that little room at the top of the tower, there is nobody else but you. You are entirely alone! The "tower" we are speaking of is your body, and the little room atop it (in other words, your world) is your brain. We shall be setting out that truth in this book. What we explain here will, in all likelihood, contradict a great many ideas and concepts that you’ve become familiar with so far. Yet it is a concrete fact based on scientific proof. Therefore, it’s impossible to reject this truth when one thinks about it in a reasoned and logical manner, instead of sticking to familiar preconceptions.