He is able to describe each alien group through his clairvoyance. Clairvoyants can commune with aliens as well as with the souls of the dead. The author tells us not to be afraid of the aliens because they, too, are messengers for our Earth even though they come from other planets we are all connected. 
Regarding crop circles, Leviton asks the question:  What message is to be found in these whirled patterns in the grain? Contrary to Marian apparitions and UFO encounters, this third sign on the Earth is visible to all of us. No one needs to possess clairvoyant ability or to be hypnotized to see them. If we are lucky, we get to walk through a freshly made crop circle. These are created in living grain. But since the late 1990s, circles have also been made in tobacco, flax, peas, potatoes, flowers, and rice paddies.  Though rare, they are even found in ice, snow, and sand.