“In thought, as in nature, there is no creation from absolute nothing.” I have taken on the daunting project of giving an account of Spinozaʼs metaphysics, and laying out the reasoning behind his doctrines. In a letter written in December 1675, barely over a year before his death, Spinoza told Henry Oldenburg that the fatalistic necessity (which was disturbing readers of his philosophy) was in fact the “principal basis” of his Ethics. Since all of his metaphysical doctrines are entwined with this necessity, it is my task to piece this puzzle together. In this thesis, I will begin by discussing his definitions and axioms, and proceed to unfold his substance monism. I will then discuss his proofs of the existence of God, followed by his doctr...