It is widely recognized that teacher-centered instructional methods cannot adequately support every child's individual needs. At a time when self-directed and action-oriented learning was not yet widely discussed, the authors of this work and its second volume, "Tomorrow Will Be Beautiful Again!" directed attention to active learning as an opportunity for mainstream schools. Both volumes are based on the principles of Maria Montessori's pedagogy and provide a wealth of practical suggestions. The authors introduce the teaching methods of Maria Montessori, give an overview of the various subject areas, and present their teaching ideas clearly and visually in both words and images. All the provided teaching materials meet the didactic criteria that Maria Montessori established for her materials: aesthetics.