This book reconstructs Spinoza's theory of the human mind against the backdrop of the twofold notion that subjective experience is explainable and that its successful explanation is of ethical relevance, because it makes us wiser, freer, and happier. Doing so, the book defends a realist rationalist interpretation of Spinoza's approach which does not entail commitment to an ontological reduction of subjective experience to mere intelligibility. In contrast to a long-standing tradition of Hegelian reading of Spinoza's Ethics, it thus defends the notion that the experience of finite subjects is fully real.