Loneliness. That was the beginning of the book.
What is left after loneliness? What do we do with so much loneliness in our hands? I resort to art. Because art is created out of loneliness with the desire to combat it - no artist is truly alone.
And I think that's the starting point of the characters in the book. They are alone. Either because they chose to be or because sometimes life forces us to be alone while we try to fight back. Except that the characters in the book get creative in the lies they tell and the ways they hide the truth, from themselves and from others.
Those who remain, in the end, are left alone and forced to live with their secrets finally exposed. They are left behind to live a ruined life. The loneliest character, the most creative, well him you better read the book to get to know. His own secret might be kept a little too long.