The "tabula rasa" of this article's title is a Latin term meaning "clean slate." For centuries before January 6, 1907, and continuing more than 100 years since, teachers have walked into classrooms of young children convinced they know full well what is good for them, and what should be poured into their minds and by what means. But on that day, Maria Montessori walked into her classroom with a "clean slate." Not the clean slate of the blackboard, or clean slates of children's minds to be filled--no, the clean slate was "her" mind! That is, she divested herself of the bric-a-brac of educational notions passed down uncritically from generation to generation; she divested herself of standard curriculum passed down unexamined as to its appropriateness for the developing human being; divested herself of traditional teaching methods blindly passed down from time immemorial; divested herself of that egotistical mind-set of "teacher knows best." On the contrary, she walked into her classroom as a scientist, passionate to lift the veil from the secrets of childhood. In this article, the author traces the events in the life of Maria Montessori that led her to pursue the concept of what people now know as Montessori education.