"Stealing" is not a legal word defining a crime. The closest legal terms would be "theft of property" or "larceny."
And the definition for those offenses is: "to take and carry away the property of another, without the consent of the owner, and with the intent to permanently deprive the owner of the use and benefit of the property."
So in short, since she did not take the book "with the intent to permanently deprive the owner...." she did not steal the book.
