The Overview Effect hypothesis originally focused on a group of people who did not yet exist, i.e., those who might fulfill the O'Neill vision and live in space settlements located at, say, L5. This is a good opportunity for me to make something very clear: I did not suggest that these space pioneers would experience a sense of awe and wonder, or that they would become instantly enlightened.

I suggested that space settlers would take for granted something that has taken human beings thousands to years to grasp: there is a unity and oneness to our planet, and we are a part of the whole system we call Earth. Since there were no space settlers when I began this work in the 1980s, I interviewed astronauts as proxies for those who would live off the planet in the future.

As I talked with astronauts, I was able to confirm the original hypothesis, but there seemed to be much more going on. They were impressed with the lack of borders and boundaries on our home world (other than those we create in our own minds or through uses of the land), and they were struck by how thin the atmosphere was. By the time the first edition was published in 1987, it had become clear to me that astronauts returned to Earth with a greater concern for the environment, world peace, and humanitarian issues.

What began as an exploration of the psychology of space settlements began to focus back to life on the surface, and the next two editions of the book did not change that perspective. In retrospect, I think the discovery of the Overview Effect as an experience that will change both people on Earth and those who live off the planet is serendipitous, as the exploration of ideas often is.

Now, though, it is time to begin looking outward at the mass migration of humanity into the solar system, and we must ask how it is going to unfold.