The book is Rare Earth. Highly recommended reading.
The gist? More fine-tuning was needed to create conditions for life on Earth than we had realized under the Drake Equation. Much more. As science progressed in the 60's through the 90's, we began to understand that the Star Trek way of thinking about life being common was just dead wrong.
Nope, the authors stay utterly neutral about God. Not mentioned on the book; they keep it to science only. Therefore, it should be readable by anyone. One of the authors was a geologist, IIRC.
Basic premise is that microbial life may be common enough Out There, but intelligent life? Probably not.
Book essentially leads you to a mild despair, with the realization that there may not be plentiful intelligent life out in the Milky Way...we could be alone, or cohabiting with only one or two races. It's not a book about science, I realized when I finished it.
It's a horror book.
It shook me up a bit.
I'd recommend it. I'd even link it, but I forgot the hypertext sandbox training I gave myself. Have to review it...later. ;)
From what I hear, it is Us, The Short Greys, The Tall Greys, The Reptilians (who may or may not like to eat us) and thats it.
Thats not a lot
The book “Rare Earth” is utter nonsense.