What is the symbolism of Jolie's novel in Porter's, Lanny?

Jolie’s novel symbolizes the tensions and consequences that may arise between personal goals and parental responsibilities. Jolie is an emerging fiction writer who has been contracted to write a crime novel. She is somewhat uncomfortable because her book is not suitable for children, and thus she cannot mention it to Lanny. Similarly, Robert’s commute and work greatly reduce his opportunities for spending time with Lanny.