The Richest Man in Babylon by George S. Clason

In all the worlds glory of technology and advances the world has not changed that much in how it´s structured especially when it comes to how money works and how society is built up because of it.

Financial Intelligence: A Manager’s Guide to Knowing What the Numbers Really Mean

Gives a good introduction to understanding balance sheets and other financial parts of a business. As an entrepreneur you need to become good with numbers and you will also need to learn how to properly calculate whether your investment will be a good one.

The Ascent of Money: A Financial History of the World
by Niall Ferguson