The foundation of Dr. Montessori's method is based on the work of three men, Pereira (a famous educator of deaf-mutes) and two French doctors, Itard and Seguin (educators of mentally handicapped persons). Montessori worked as an assistant instructor in the Psychiatric Clinic of the University of Rome where visited the insane asylum to choose subjects for clinical instruction. This was the reason why Montessori got interested in mentally handicapped children, who were housed in the same institution. Dr. Montessori's interest in these children made her familiar with Seguin's teaching method for these unfortunate children and with Itard's experiments. She applied the lessons she had learned from these early experiences along with additional materials she developed herself to the education of her disadvantaged children in Rome. These children took the state exams in Rome, and they passed the exams and outperformed many normal children.

Montessori's experiences and studies led her to the conclusion that mental deficiency was more often an educational failure than a genuine medical problem.

The first opportunity Montessori had to apply her method to normal children was in Rome, in the first institution known as "The Children's Home” in 1907. This institution had about fifty children between the ages of three and six. The results amazed her. The children not only learned but they became self-disciplined and organized and their movements were more coordinated. The children showed interest and joy when they worked. Montessori allowed the children to choose their own work.

Montessori's observations, revealed to her and to the world, characteristics of the children's personalities never seen before. This is how the Montessori method was born.

Montessori's method is based on three important principles: the prepared environment, the teacher, and the child.

These three important factors work in conjunction.

The environment of the Montessori classroom literally fits the child. The working materials and tools used in the classroom are all child-sized, which provides better physical and cognitive development for the child.

The prepared environment contains sensorial materials for learning in a variety of areas. These materials help the child to go at his own pace to discover the various prepared paths. The materials are designed to assist the child's physical, emotional, mental, social, and spiritual development.

The teacher is also part of the environment. The teacher’s job is to assist the child to do things all by himself. She is a guide who helps the child perform his own activities by himself and intervenes only when necessary. This allows him to reach his potential through his own efforts, leading to self-realization.

The child enters into communication with the environment and comes to love it. He directs himself and chooses his own work. The teacher maintains respect for the child’s personality and choices. The child becomes conscious of his own powers.

The child has the freedom to live in the environment and to absorb knowledge through his senses. Montessori said, “The impressions the child gets from the environment not only penetrate into his mind, but they form it: they become incarnate."

Maria Montessori was the first female medical doctor in Italy. She studied philosophy and psychology and became a specialist in the nervous diseases of children.

The chair of the School of Anthropology at the University of Rome, Dr. Maria Montessori received the honorary degree of Doctor of Philosophy in her last years of life.

After receiving her M.D. in 1896, she worked as an assistant doctor at the Psychiatric Clinic at the University of Rome. She became interested in the children who were classified as mentally delayed and quickly discovered that the apparent mental deficiency of these children was frequently a consequence of poor pedagogical practices.

When she formed a group of teachers to observe and educate "feeble-minded" [sic] children, she established her pace as the founder of scientific pedagogy in Italy. She had spectacular success: many of her supposedly delayed pupils learned to read and write and were able to compete favorably with supposedly normal children in tests of intelligence.

Dr. Montessori became convinced that the same methods used with the less-intelligent children such as careful observation, teaching them twelve or more hours a day, making notes and charts, comparing, analyzing, and preparing new materials and lessons for the next day, could be applied to ordinary children in order to develop and set free their personalities in a better and more productive way.  In 1907, she was invited to become the Director of the first Casa de Bambini in a working-class district of Rome.  This "Children's House" for poor children (socially, economically, and intellectually disadvantaged, but mentally normal) became the prototype of the ultimate Montessori approach to education, emphasizing scientifically-designed educational materials and lessons, child-sized furniture, practical activities, a well-organized environment, and self-discipline.

Many believe Maria Montessori to be the woman who gave meaning to childhood education. Through her work and research, she changed the thinking and opinion of what a child is capable of when treated with love, patience, respect, and freedom of self-chosen work.