Epictetus said: "Happiness and freedom begin with a clear understanding of one principle: Some things are within our control, and some things are not. It is only after you have faced up to this fundamental rule and learned to distinguish between what you can and can't control that inner tranquility and outer effectiveness become possible."

The most powerful principle for turning your knowledge of freedom into huge personal advantages is to focus on what you control in order to bring you both short-term and long-term benefits.