Here are 2 books I would recommend anyone to read :
1. The E-Myth Revisited by Michael E Gerber.
The E here stands for Entrepreneurial , not anything to do with email or ecommerce. A definite read for anybody thinking about starting out and great to help focus you if you are finding running a business a chore. My opinion is that his views might be hard to follow to the letter, but if you take the general idea, you can see immediate benefits.
On Amazon: The E-Myth Revisited
2. The Goal by Eliyahu M. Goldratt
For anyone involved in Production, this is a well told story of solving problems in a marraige at the same time as trying to save a failing company. Hard to put down as you are eager to see how both problems are solved. By employing some diverse thinking like reducing efficiency in some areas to help the overall process, this book can help you think outside the box.
On Amazon : The Goal