Who is Lillian Moller Gilbreth from Cheaper by the Dozen and what is their importance?

Lillian Moller Gilbreth is Frank's wife and the mother the twelve Gilbreth children. She and her husband both dreamed of having a large family. Lillian is described as quiet, well-bred, firm in her beliefs, and having a great sense of humor. She is deeply in love with her husband, and her biggest concern about childbirth is that her children will hear her screams.