Whoever teaches learns in the act of teaching, and whoever learns teaches in the act of learning.

Paulo Reglus Neves Freire (1921 CE-1997 CE), Paulo Reglus Neves Freirewas a Brazilian educator and philosopher who was a leading advocate of critical pedagogy. His influential work Pedagogy of the Oppressed is generally considered one of the foundational texts of the critical pedagogy movement, and was the third most cited book in the social sciences as of 2016 according to Google Scholar.