Contact by Carl Sagan
For the first time humans receive a signal from outer space. They have to deal with decrypting the message and deciding weather to build this machine or not. Not to mention the religious groups breathing down their backs about it being god. The book really makes you think. I strongly recommending reading it and seeing the movie.

Stephen Hawking's Universe: The Cosmos Explained by David Filkin
Excellent book all of you who want to know about astronomy and cosmology. From black holes to time warps this book has everything in it! Most of my explanations on my Phenomena section came from reading this book.

Astronomy by Dinah Moche
If your a newbie astronomer you have to read this book. This has everything first time astronomers need to know about it.

Cosmic Questions by Richard Morris
I'm running out of comments to make about these books. Let's just say I'd never waste my time typing this up if these were bad books. Again, this is a great cosmology book.

365 Starry Nights: An Introduction to Astronomy... by Chet Raymo
This book is a great way for a beginner to learn the night sky. It doesn't require any previous knowledge of the heavens. No need to start at the beginning just turn to the month in question and start reading. What's visible on a particular date in the sky is presented in black and white drawing with text giving a brief description about it.