Greg Quigley sent me a Facebook text message asking:

“Hey Stephen, enjoying the Mapped Space books, great work. I just finished up In Earth's Service and had one question. What kept other civilization from claiming Earth before sentient beings evolved? It's mentioned that on Ansara they have trees that were transplanted from Earth millions of years ago. That implies other alien civilizations had visited Earth yet none had claimed it.”

The answer is now on my website with some graphics and a little more detail in the answer

http://www.stephenrenneberg.com/Comme...

Regards,

Stephen