Since my early 20s I've been trying to increase my knowledge of money and how money works. A main goal is to be able to retire sooner rather than later. More importantly, I want to make sure that if I loose or quit my job later in life that I don't have to worry about finding another one.
In this search for knowledge I've read a decent number of books across several financial topics. Investing, personal finance, financial planning, etc... I think that one of the best ones is also one of the simplest, "The Richest Man in Babylon" by George S. Clason.
Your local library might have it, but if not, it's worth picking up. It helps drive home the fact that you are going to have to take care of yourself when it comes to your money and that in order to do this you have to save. The central idea of the book is to save 10% of everything you earn. The book does a great job of showing you how to think about this and had answers to all my natural reactions.
I want to make sure that everyone I know can get to the point where they are working because they want to and not because they have to and I think this book is a huge step in the right direction. It's a very simple idea, but powerful ones often are.