How can we educate children, instruct them and build their freedom without taking a global approach to them, ignoring everything about their environment and surroundings? How can we truly consider them as fully-fledged human beings, with all their intellectual and physical potential, as well as their playful and spiritual potential? These were the questions posed by the great pedagogue Maria Montessori (1870-1952) over a century ago. While the first volume of Pédagogie Scientifique focuses on the founding experience of the "Maison des Enfants", the second delves more deeply into themes dear to the author concerning elementary education. These include the role of the body and the preparation of teachers, the atmosphere in the classroom, the place of attention and willpower, imagination and intelligence. A major contribution to educational theory.