Who is Frank Bunker Gilbreth from Cheaper by the Dozen and what is their importance?

Frank Bunker Gilbreth is married to Lillian. He and his wife have twelve children. Frank is described as a tall, robust man, who exudes confidence. He is hard-working, a proponent of education, and a successful businessman. Frank is the novel's main character, and he is said to be full of pranks and good humor. His children adore him.