Mere Christianity
Why Christ is the best option
This is the most important book you can read after the Bible. If you are searching for the meaning of YOUR life, if you think there's gotta be more than what we see and perceive in our earthly existence, if your heart tells you to honestly seek for the truth, look no further; no other book will help you discover it. Actually God is reachable to everyone. You only have to be willing to put aside those obstacles in your vision. C.S. Lewis is not out there to "get you", nor preach to you. He'll help you figure it out for yourself better than any other philosopher or scientist can.
Some people will start looking for God by means of their intellectual curiosity, others will do it out of despair and sheer anguish, and others simply draw near Him out of love for His Son Jesus Christ. Whatever means to start your search is good as long as it is honest. (And remember that faith is a gift that God gives you, not that you give to yourself).
The book deals in its first short chapters with Natural Law, and it explains the difference with the laws of nature, e.g. gravity, etc. The language is simple enough for anybody to understand (if I understand it anybody can). Natural Law is still one of the unrefutable evidences for the existence of God that nobody can deny, or explain. Human Genome Project founder Francis Collins explains this very clearly too in his book 'The Language of God'. By the way, Collins says that the other choice we, humans, have in order to understand our nature is accepting that life is the result of an infinite series of miraculous "coincidences" or chances, whose probability are, each one of them, infinitely small.
I am reading this book for the second time, now in Spanish. I am underlining almost every line. There is so much to think about here. But I'd like to quote the following lines:
"In religion, as in war and in everything else, consolation is the only thing that cannot be obtained by searching for it. If you look for the truth, you may find consolation in the end. If you look for consolation you will not find neither consolation nor the truth... only empty talk and preestablished conceptions to start with, and in the end, despair."
And this reminds me so much of one of Peter Kreeft's funny stories: When you were a child and believed in Santa, it made you feel comfortable and happy. Then why, when you grew up, did you stop believing in him? Why care for the truth if you can be happy?
Approach it honestly; don't be so arrogant and take the challenge.