Spinoza studies seemed to revolve almost exclusively around metaphysical issues for centuries. In these last few decades, this situation tended to change – mainly prompted by French neo-Marxist studies in the 1960s – insofar as there has been recognition of an original political philosophy deeply rooted in Spinoza’s ontology. Nevertheless, to this day only seldom have studies appeared focusing on the axis around which these two dimensions of the system are articulated – an axis that could be expressed in the formula ‘law, or power’, which by itself would epitomize at the outset a slogan for a radically new version of modern natural law. This book’s first task is to expound and argue with Spinoza’s conception of natural law from inside that axis. This makes it a book on Spinoza’s natural law theory and, consequently, probably the first major book dedicated to his Philosophy of Law entirely from the viewpoint of his internal connection between metaphysics and politics. That is why it must be interdisciplinary in nature, going from basic metaphysical premises toward specific political purposes, and involving a reconstruction of concepts usually associated with the modern natural law tradition (such as the individual, right, law of Nature, the State, the social contract, freedom, etc.). Together, they represent the extent of Spinoza’s revolutions in natural law.