Dewey's idea of the secondary school emerged during the first thirty years of his academic career as he responded to historical realities and contemporary changes in secondary education in the United States. His advocacy of applying subject matter to the life of the student and to the life of society, integrating subject matter, an expanded curriculum that included express concern for vocation and avocation, conducting the school in a social democratic spirit, and establishing a unitary system of secondary education that would mitigate class divisions that he saw as fatal to democracy eventually found generalized expression in "Democracy and Education."