Cheaper by the Dozen is a biographical novel written by Frank Bunker Gilbreth, Jr. and Ernestine Gilbreth Carey, published in 1948. The book was adapted to film by Twentieth Century Fox in 1950. The book tells the story of time and motion study and efficiency experts Frank Bunker Gilbreth and Lillian Moller Gilbreth, and their twelve children, as they reside in Montclair, New Jersey for many years.