Classicly

Montessori Children is a book on the theory of education written by Carolyn Sherwin Bailey, an American children's author. 

Preface from the book:

As a student of child psychology and always most deeply interested in the welfare problems that confront us in connection with the upbringing of little children, I went to Rome in 1913 to study, first-hand, the results of the Montessori system of education. A great deal had been written and said in connection with the technic of the system. Little had been given the world in regard to individual children who were developing their personalities through the auto-education of Montessori. I wished to observe Montessori children.