Belief comes easily for Lewis: "Not that I am (I think) in much danger of ceasing to believe in God. The real danger is of coming to believe such dreadful things about Him. The conclusion I dread is not: 'So there's no God after all,' but 'So this is what God's really like. Deceive yourself no longer.'...Of course it's easy enough to say that God seems absent at our greatest need because He is absent -- non-existent. But then why does He seem so present when, to put it frankly, we don't ask for Him?" (Lewis, p. 5) In short, Lewis is tormented by the question of how can one believe in a good God, a God worthy of belief, in a world of suffering, where loss is part of human existence? Chapter 3

Ultimately, even in a world riddled with loss, Lewis insists on affirming the goodness of the world, and the goodness of the God that created that world. He uses metaphors not simply of heaven, but of the common, human daily activities of eating, drinking, and the memories he spent with his wife. "Delicious drinks are wasted on a really ravenous thirst. Is it similarly the very intensity of the longing that draws the iron curtain that makes us feel we...

He realizes that death is a part of life. In taking his wife, "God has not been trying an experiment on my faith or love in order to find out their quality. He knew it already. It was I who didn't." (Lewis, p. 52) God knows the quality of the believer's faith better than Lewis knows his own heart -- He knew Lewis would doubt and then return, God was not playing a cruel joke. "He always knew that my temple was a house of cards. His only way of making me realize that fact was to knock it down," but God also knew Lewis would return to his belief in a more sober, if less immediately and simply joyful fashion. (Lewis, p.52)
Works Cited

Lewis, C.S. A Grief Observed. San Francisco: HarperCollins, 2001.