This novel takes contrary ideas of many kinds and combines them, leading to a deep appreciation for the strange ineffable sadness and thrill of the human life. The central idea is love, but Evan's conception of love is one that encompasses both happiness and mourning, joy and death. For instance, The Letter in question is discovered over the death of a child, which contrasts the elements of new life (the child) and death.
Other important contrasts in the novel include the central role of the Christmas season, with its hopefulness, and also dread. The timeless quality of the holiday is a bitter backdrop for the untimely death of a child, and the promise of struggle and death that the characters face throughout the novel. All this darkness is like a background on top of which is painted the love story between David and MaryAnne.
If the love story seems out of place, that might be the point, because the love between them must survive the tests of their somewhat tragic, difficult lives. In the same way, the hope of the Christmas season, although it brings chipper happiness to some, brings emotional challenges to others. The question of the novel seems to be whether love is a force that could be a legitimate response to human suffering and death, which happens to be the central question of Christmas as a religious holiday.
