What are the motifs in Maria Montessori: Her Life and Work by E. M. Standing?

The entire Montessori System is based upon making observations about children, and properly designing an entire educational methodology surrounding a realistic assessment of the child's needs. This is rooted in some spiritual and philosophical beliefs. Maria Montessori believed in God, and she was able to somehow both make this very clear without offending others with her faith. Her beliefs also tended to follow Aristotle, for whom the spirit of an entity and the body of it are a constant living unity.