Willem van Blijenbergh was a Dutch grain broker who had authored a work condemning atheism and defending revealed religion in 1663, a year before beginning his correspondence with Spinoza. After reading Spinoza’s DPP and CM, he wrote and raised many awkward questions. The correspondence between the two men amounts to eight letters, four from each (Ep18–24, Ep27). Some commentators have suggested that Blijenbergh was obtuse. Although he surely was a frustrating interlocutor (Spinoza’s final letter, requesting him to desist from further correspondence, is a study in polite forbearance), contemporary scholars arguably should be grateful for his dogged persistence which resulted in Spinoza offering uncharacteristically detailed expositions of his views on the problem of evil, free will, sin, and the nature of God. Of course, these four topics are intimately interrelated, as these letters so brilliantly demonstrate.