There's a great book called The Intelligent Investor. It's a pretty old book, but the author was Warren Buffett's mentor. If you decide to get it, make sure you get the most recent version. At the end of each chapter it has a commentary on the entire chapter and shows you how to apply it to today's standards. Since the original book is close to 100 years old, some of it is undoubtedly outdated which is where the commentary for each chapter comes in extremely handy. I picked it up a couple of weeks ago and learned a few things that I would like to apply.