This book is a defense of freedom. It is addressed to those who argue that freedom is incompatible with a scientific worldview, as well as to those in the political arena who are willing to sacrifice freedom for a seemingly higher purpose. The two issues are addressed in the context of each other. Freedom appears to be a multidimensional phenomenon, whether its existential (ontological) and metaphysical aspects, or its political or personal aspects. Consequently, one of the core ideas of this book is simply that many of the difficulties we encounter in understanding freedom stem from the mixing of diverse concepts of freedom. For example, we use the concept of political freedom to explain personal freedom, or vice versa. Therefore, it was important for me to write a substantial book in which I could attempt to understand how concepts of freedom at many different levels relate to and diverge from one another. The valuable contribution the book makes in this sense is more its treatment of the general concept of freedom than its subjective components. At the same time, I believe I have made many new contributions along the way in terms of my interpretations and critiques of different philosophies and theories.