I'm now reading Contact by Carl Sagan. I've seen the movie plenty of times, but a long time ago, and until recently I didn't know it was based on a book.
So far the book is great. It's really nice to read Dr. Arroway's thoughts about things, it explains a lot. It also provides a lot more background from her life, which is also nice. And the story is great, and also written well. I'm really glad I found out about the book and ordered it.