Ellen Karolina Sofia Key (Swedish pronunciation: [kej]) was a Swedish difference feminist writer on many subjects in the fields of family life, ethics and education and was an important figure in the Modern Breakthrough movement. She was an early advocate of a child-centered approach to education and parenting, and was also a suffragist.She is best known for her book on education, Barnets århundrade (1900), which was translated in English in 1909 as The Century of the Child.
