Everybody has a strong intuition that our voluntary actions are free, but where does this freedom come from? Most "libertarians", i.e., those who believe that our behavior is really free, argue from a philosophical, spiritual, social, or cultural background. The arguments do not look very convincing, because we know that we are not only social and spiritual beings, but also biological organisms steered by the brain. On the other hand, biologists and psychologists tend to deny the reality of freedom of our actions. They assert that these actions are causally determined by brain processes, and that the brain, for some unknown reason, creates an illusion of free will and voluntary intention. This book takes a completely different stance.