It is impossible for us to conclude a book on extra-terrestrials without mentioning Our Ancestors, Those who came to Earth so long ago.
We cannot say that They no longer exist, because each race left its genetic inheritance in the human gene pool. So in a way They are ALL still here.
The first and most important race was The Hashons. (Pronounced hay'-shuns) They evolved from a lizard-like creature that developed over the ages many mammal-like traits. They became warm-blooded, they nursed Their young. The Hashons developed a great civilization based on The Teachings Of Spiritism.
They were bold fighters but not a conquering people. If left alone They did not bother others.
Their Home World, Hades, was a harsh world. It did not have oceans like Earth, but instead, six great lakes in its temperate regions. About its equator was a vast desert that, for many generations, was impassable in the summer.
The Hashons' love of freedom and justice was so strong that They were never really completely subdued, though one race tried.....
The Havens. The Havens evolved from a bat-like creature that developed arms and then began to walk upright. The Havens were a conquering people. They lived in a vast Empire which existed for the soul purpose of extending the power and dominion of their Lord God. All the energy of their society was directed towards this purpose. Every aspect of life was directed to this goal!
Their original home world was beautiful, very like Earth, except that none of its continents lay on the equator, and a vast ocean surrounded the middle of their world.
The Haven philosophy of domination and destruction of all that is different unfortunately still exists within the genes of human kind. But it is hoped that some day it will pass away, and be a forgotten nightmare.
The last of Our Ancestors were The Peepians. (Pronounced Pee'-pians.) The Peepians resembled humans except that they had only one eye in the middle of their forehead, and three fingers, and a thumb, and four toes. They had once been an aggressive people, but when their world was devastated by the senseless war that swept their solar system they developed a new religion of brotherhood and harmony passed on the teachings of their great Lord Change.  When they were found by The Havens they were a unified people that resisted their conquest bitterly. They eventually joined with The Hashon Republic and the bitter struggle against The Havens and Their Godden Empire eventually brought the last few survivors here to Earth, where their physical forms perished, but Their Spiritual Forms continued to fight the battle against tyranny and aggression.
Our knowledge of The Old Races is what has made us so popular with the extra-terrestrials. They are very curious to see if a world so corrupted can survive. We intend to show them we can!!