Rationality of faith in God 

... has been the discovery of my lifetime.

That it should take a discovery to establish a truth known to most people in most ages speaks volumes about the times we live in. That it should take a whole journey to come to terms with the fact is something of a surprise. That a man devoid of theological pretensions should go on such a journey, and report on it, is a greater surprise still.

Faith is reasonable. I have discovered the obvious and wrote a book about it. Only in an intellectual climate that underrates the power of both reason and faith is such a discovery conceivable and necessary.

Reason and belief have both been compromised by mutually exclusive extremes. Atheism first reduced reason to science, and then debunked all belief in the name of reason, just as New Age first inflated the claims of belief and then promoted any belief in defiance of reason. And the spirit of our age has been equally comfortable with both.
Can atheism and New Age be reconciled? Is there perhaps another solution, a sort of middle road—combining strengths of both and avoiding their weaknesses? My discovery has been precisely that there is such a solution, and that solution is Catholic Christianity. 

The atheist builds his world view on objectified perceptions; the New-Age practitioner builds his on subjective spiritual experiences. Each refuses to admit the validity of the data that the other claims fundamental to his own position. 

But, suppose we persuaded the atheist to relax his requirements and to open his mind to a possibility of the supernatural; and suppose we suggested to the New-Ager that he interpret his spiritual experiences in the light of reason? Ah, that would be a whole different story! That's the story I will tell you if you decide to reach for By Reason Alone.  

The extremes of atheism and New Age can be overcome. The great divide can be healed. Reason can lead to faith and both can offer valid insights. The greatest minds in the history of mankind talked intelligently about faith and so did scores of saints over the centuries. But if reason is to explore the truths of faith, it must shed the yoke of both materialist presuppositions and subjectivist credulity. Mystics will then be free to converse with philosophers. 

These could be but bold assertions. You are 250 pages away from seeing for yourself whether they are true.