When she was 12, the family moved to Rome to take advantage of the better educational facilities. An interest in engineering technology and mathematics led her to enroll in classes at a technical institute at the age of 14. Later an interest in biology led to her decision to study medicine. This decision required some courage and tenacity, as it was in utter defiance of the customs of a society which excluded women from such endeavors.

 In 1894 Maria Montessori became the first woman to receive a medical degree in Italy. Her experiences in the pursuit of this degree reinforced her already well-developed feminist ideas. Throughout her life she was a frequent participant in international feminist congresses.

Maria Montessori's first appointment was as an assistant doctor in the psychiatric clinic of the University of Rome, where she had her first prolonged contact with mentally challenged children. She became convinced that the problem of handling these defectives was as much one of instructional method as of medical treatment. In 1898 she was appointed director of the State Orthophrenic School in Rome, whose function was to care for the "hopelessly deficient" and "idiot" children of the city. She enjoyed tremendous success in teaching the children herself, while refining and applying her innovative methods and training other teachers to work with the children.

In 1901 Dr. Montessori left the school to pursue further studies and research. At the same time she was holding the chair of hygiene at the Scuola di Magistero Femminile in Rome, where she was also a permanent external examiner in the faculty of pedagogy. In 1904 she became a full professor at the University of Rome and from 1904 to 1908 held the chair of anthropology there. She was also a government inspector of schools, a lecturer, and a practicing physician.

In 1906 the Italian government put Dr. Montessori in charge of a state-supported slum school in the San Lorenzo quarter of Rome which had 60 children aged 3 to 6 from poverty-stricken families. By this time her early successes with mentally challenged children suggested to her the idea of trying the same educational methods with normal children. Dealing with these children, she used what she termed a "prepared environment" to provide an atmosphere for learning, that is, small chairs and tables instead of rows of desks. The basic features of the method are development of the child's initiative through responsible individual freedom of behavior, improvement of sense perception through training, and development of bodily coordination through games and exercise. The function of the teacher is to provide didactic material, such as counting beads or geometric puzzles, and act as an adviser and guide, staying as much as possible in the background.

 Dr. Montessori's view of the nature of the child, on which the Montessori method is based, is that children go through a series of "sensitive periods" with "creative moments," when they show spontaneous interest in learning. It is then that the children have the greatest ability to learn, and these periods should be utilized to the fullest so that the children learn as much as possible; and they should not be held back by non-natural curricula or classes. Work, she believed, is its own reward to the child, and there is no necessity for other rewards. Self-discipline emerges out of the independence of the atmosphere of learning.