More than a century after the first Montessori school opened as part of an urban renewal project in Rome, Italy, Montessori education continues to thrive. Montessori schools exist on six continents, with upwards of 5,000 in the U.S. alone.

Maria Montessori, one of Italy's first female physicians, began her career as an educator with poor children in the San Lorenzo district of Rome. As she worked with these children, carefully observing their activity, she also experimented with an array of manipulative materials designed to assist the children's learning. Over the course of 50 years of experimentation and observation, the materials - beads, rods, spindles, sandpaper letters and numbers - evolved into a complex and remarkable collection of apparatus, which today comprise the basis of the prepared environment.

These hands-on, self-correcting learning tools enable the child to explore new concepts independently, to build knowledge sequentially, and to pursue mastery in an individualized manner. While the materials are easily the most visible aspect of Montessori education, other elements are equally important to the success of the method.

Essential Montessori elements include:

1. Mixed age grouping, which fosters independence, cooperation and discovery;
2. Large blocks of uninterrupted time for self-directed work;
3. An environment that allows for maximum freedom of movement and choice;
4. An overall emphasis on intrinsic motivation rather than rewards or punishments;
5. Specially prepared adults who are skilled at observation, preparing an environment, and interacting with children in positive, respectful ways.

Human development is the central focus of Montessori education. Maria Montessori mapped four "planes of development," each with its own special characteristics and needs. The first level of development occurs from birth to age 6. At the stage children are sensorial explorers, constructing their intellects by absorbing every aspect of their environment, their language and their culture. From age 6 to 12 children become conceptual explorers. They apply their powers of abstraction and imagination, to discover and expand their worlds further. Montessori Schools are organized to reflect these stages: Primary classrooms, 3-6 year-old, Lower Elementary, 6-9 and Upper Elementary, 9-12.

Research on Montessori has begun to shed much needed light on both the history and culture of the movement and the factors that contribute to its success. Psychological research, in particular, has validated many of the core principles of the method, including mixed-age grouping, differentiated instruction, interdisciplinary study, and intrinsic motivation. This growing knowledge base provides insight and evidence for importance of these and other factors in fostering optimal settings for students to not only achieve at high levels, but to develop life-long habits of confidence, persistence, critical thinking, and love of learning.