Rare Earth: Why Complex Life Is Uncommon in the Universe
by Peter Ward, Donald Brownlee
This is my current read, already changed my whole outlook on this topic.
That was a fine book. The authors are actual scientists with their heads screwed on tight. It happens that I totally agreed with their premise before they wrote the book, but when the book came out, although we are probably alone, I was no longer alone in that view. The book signaled a landmark change in direction of popular thought on the topic.
Rare Earth is exceptional as is Darwin's God.
As was pointed out, Rare Earth is not written by "religious" scientists. I do not recall God being mentioned at all. Darwin's God is written by a Christian who is not a creationist.
There were some posts about how we are finding that the Universe and Earth is much more complex than we originally thought. That is science's part. From that God becomes more complex than we originally thought (which is one of the conclusions of Darwin's God). That is religion's part. In both cases, it is man's arrogance that assumed both were simple, since that brings God and the universe down to our level.
It would be nice to know we are not alone in all this, but not really necessary if you believe in God. If you do not believe in God, it is imperative that we are not alone.