Maria Montessori's life...

Maria Montessori was born in Italy in 1870. Proving her exceptional qualities, she became the first woman to graduate in medicine in Italy. She became increasingly interested in the needs of children and in the year 1904 she started giving pedagogy and anthropology lectures at the University of Rome.
In 1907 Montessori started in Rome a so-called "Children's house". Children's House was a child care center in an apartment building in the poor neighborhood of Rome. She was focused on teaching the students ways to develop their own skills at a pace they set, which was a principle Montessori called "spontaneous self-development". The success of this school sparked the opening of many more, and a worldwide interest in Montessori's methods of education.
Montessori's broader vision of education consisted of the idea that children should be helped to develop into good human beings. In later years "Education for peace" became her guiding principle.
When Maria Montessori died in Holladn in 1952, the Montessori method was a widely acclaimed educational concept with scientific recognition and many dedicated followers.

...and her philosophy:

Aside from a new pedagogy, among the premier contributions to educational thought by Montessori are:

• children as natural learners
• instruction of children in 3-year age groups, corresponding to sensitive periods of development (example: Birth-3, 3-6, 6-12, 12-15 year olds with an Erdkinder (German for "Land Children") program for early teens
• children as competent beings, encouraged to make maximal decisions
• observation of the child in the environment as the basis for ongoing curriculum development (presentation of subsequent exercises for skill development and information accumulation)
• small, child-sized furniture and creation of a small, child-sized environment (microcosm) in which each can be competent to produce overall a self-running small children's world
• creation of a scale of sensitive periods of development, which provides a focus for class work that is appropriate and uniquely stimulating and motivating to the child (including sensitive periods for language development, sensorial experimentation and refinement, and various levels of social interaction)
• the importance of the "absorbent mind," the limitless motivation of the young child to achieve competence over his or her environment and to perfect his or her skills and understandings as they occur within each sensitive period. The phenomenon is characterized by the young child's capacity for repetition of activities within sensitive period categories (Example: exhaustive babbling as language practice leading to language competence).
• self-correcting "auto-didactic" materials