Lewis's fame in the 1940s rested largely on his work as a Christian apologist – that is, a defender of the faith by means of rational argument. So little did Lewis seek this kind of fame that, when he was first approached by a publisher who had been impressed by The Pilgrim's Regress and Out of the Silent Planet, and wanted Lewis to contribute a book ‘on pain’ to the ‘Christian Challenge’ series, Lewis wished the book to appear anonymously. He did not get his way, although, when The Problem of Pain was published in 1940, it did contain a preface in which Lewis disclaimed any particular suitability to write as a Christian theologian on the subject of pain. The only purpose of the book is, Lewis says (perhaps none too modestly), ‘to solve the intellectual problem raised by suffering’ (PP, p. vii). This socalled problem of evil, a central issue in any defence of Christian belief, is addressed in ‘theodicy’ – that is, the attempt to vindicate the justice (Greek dikē) of God. The case against God is very clear and long established. Lewis sums it up thus: ’ ‘‘If God were good, He would wish to make His creatures perfectly happy, and if God were almighty He would be able to do that if He wished. But the creatures are not happy. Therefore God lacks either goodness, or power, or both.’’ This is the problem of pain, in its simplest form’ (PP l4). If Lewis's formulation recalls countless examination questions from introductory Philosophy of Religion courses, it also gives one reason why Lewis himself was for many years an atheist. He begins his book with the case against God of Lewis the atheist; the indictment is in essence the same as the classical formulation given above, but is expressed with a rhetorical panache typical of Lewis: