Who is Spinoza from The Story of Philosophy and what is their importance?

Spinoza concludes that the object of philosophy is to perceive unity in diversity, mind in matter, and matter in mind. He seeks the synthesis where opposites and contradictions meet and merge. He believes the highest knowledge of universal unity is the intellectual equivalent of the love of God. The mind knows the external world only through the sensation and perception that the world impresses on the mind. Spinoza accepts Descartes conception that there is a homogeneous substance under all forms of matter and another homogeneous substance underlying all forms of mind. These two substances challenge Spinoza's theory of unity.