Russell’s critique of substance monism is an ideal starting point from which to understand some main concepts in Spinoza’s difficult metaphysics. This paper provides an in-depth examination of Spinoza’s proof that only one substance exists. On this basis, it rejects Russell’s interpretation of Spinoza’s theory of reality as founded upon the logical doctrine that all propositions consist of a predicate and a subject. An alternative interpretation is offered: Spinoza’s substance is not a bearer of properties, as Russell implied, but an (...) eternally active, self-actualizing creative power. Eventually, Spinoza the Monist and Russell the Pluralist are at one in holding that process and activity rather than enduring things are the most fundamental realities. (shrink)