What is the theme in The Shipping News by E. Annie Proulx?

For Quoyle, this story is one of coming of age. Although he is an adult of thirty-six years when introduced to the reader, he is very immature. He has very little, if any self-esteem, he's drifting through his life. After becoming a father and living through the destructive marriage to Petal he begins to grow up a little. However, not until he leaves New York and arrives in Newfoundland does he really begin to experience some small successes in his life and mature.