Maria Montessori is one of the most appreciated names in the history of preschool education. She has dedicated her life to children, representing their rights and their individuality. This paper is about her life and things for which she fought and achieved. Her parental method was based on observing children. She involved all her knowledge from few collages that she attended. This paper describes anthropological, pedagogical, and psychological assumptions of Montessori method. It describes the development of a child through stages and their most sensitive periods. In her method, Maria Montessori nurtures seven principles which are described in this paper. This principles are: respecting a child, senses and movement training, attention polarization, freedom of choice, prepared environment, the role of the educator, and the main thought: „help me so I can do it alone“. Through this paper the characteristics of educating the creativity movement as well as cosmic and religious upbringing are described. An educator has an important role in fulfilling child's needs. Educator's good personal, internal, and professional preparation are of extreme importance, as well as the prepared environment is. This paper presents the role of an educator and their desirable characteristics. In the last chapter, Montessori accessories and work materials are described, as well as the criteria for their selection.