Ernestine Gilbreth Carey, whose lighthearted memoir, "Cheaper by the Dozen," detailed the frenetic life of a family with 12 children and inspired several films, has died.

Carey died Saturday of natural causes at St. Agnes Medical Center in Fresno, her son Charles Carey Jr. said. She was 98.

"Cheaper by the Dozen," which Carey co-wrote with her brother Frank Gilbreth, became a best seller when it was published in 1948.

The book documented the adventures of the Gilbreth clan, which included six sons and six daughters and parents Lillian Moller Gilbreth and Frank Bunker Gilbreth, management experts who focused on the science of motion study and industrial efficiencies.

"Cheaper by the Dozen" was adapted into films starring Clifton Webb, Jeanne Crain and Myrna Loy in the early 1950s, and was remade in 2003 with Steve Martin and Bonnie Hunt. A sequel followed in 2005.

The siblings also co-wrote "Belles on Their Toes," which was also turned into a film.

Carey had only two children herself after taking care of younger siblings for much of her life when her father died while she was still a teenager.

The third of the family's 12 children, Carey outlived nine of her siblings.

Born in New York City, Carey graduated with an English degree from Smith College and worked for years as a buyer at Macy's department store in New York before taking up writing.

Carey is survived by Charles and her other child Lillian Carey Barley, her brothers Frederick and Robert, six grandchildren and seven great-grandchildren.