In a Montessori classroom, there is no front of the room and no teacher's desk as a focal point of attention. Stimulation from learning comes from the total environment. Dr. Montessori always referred to the teacher as a "guide" because her role differs considerably from that of a traditional instructor. She demonstrates the correct use of materials as they are individually chosen by the children. She carefully watches the progress of each child and keeps a detailed record of his work. Each teacher has been trained to recognize individual periods of readiness.