In Rules, by Cynthia Lord, the surname of David and Catherine is never actually given. Yet, by doing a little research, it can be presumed that David's last name could actually be Lord, due to the fact that the novel's author, Cynthia Lord, essentially wrote the book about her own family's method of dealing with autism. In a Q&A at the end of the novel, Lord writes, "I have two children, a daughter and a son, and my son has autism. One day when my daughter was about ten years old, she asked me, 'Mom, how come I never see families like mine in books and on TV?' "

Most likely, the reasoning behind Lord's decision in not giving David and Catherine a definite last name is to make them arbitrarily relatable to any reader. In this sense, a reader can see David as being a member of their own family (or, perhaps, as his/herself). The two children no longer have to seem fictional to the reader. They can appear very real, familial, and relatable. While David and Catherine were based heavily off of the author's own children, any surname can be given to them, though 'Lord' is the most rational choice.