What is one good way to understand how a book affects different people? Read an article about the author.
Ask different people for their opinions.
Read the book several times.
Watch a movie based on the book.

To grow up can mean many different things. Normally, it is reffered to as the act of literally growing older. Legally, a minor becomes an adult at age 18. In other circumstances, "growing up" can mean to physically and mentally mature to a specific points. Grown ups are usually calmer and less childish. When one grows up, the become less childish and understand things in simpler ways.

Explanation:

Hope that's good enough.