The late Paulo Freire of Brazil-teacher, philosopher, and activist-is widely regarded in the U.S. and elsewhere as one of the most influential educators of the 20th century. He is the author of more than 20 books, which have been translated and sold widely throughout the world. Among his many books are the classic Pedagogy of the Oppressed (ISBN 0-8264-0611-4) and Letters to Christina (ISBN 0-4159-1097-8).