Notably absent from much historical study has been the story of the common person of past ages. This upper class bias of historians has not, in the main, been motivated by ideological concerns. Rather, historians have not had data about the common folk. These people never left many records. Most were illiterate.
History is made up of interpretations of written records.
Thus, exit the common folk as a subject for history. Aries turned all that upside down. His book found new ways of understanding the past, and his methods unlock the story of common families and the youth of these families. Hundreds of books have been written since 1963 in the area of the history of childhood, and are deeply indebted to Aries for his methods of inferential history. On Aries' view, childhood is a very new concept.