This book is about textbooks, textbook quality and quality standards of textbooks. From a theoretical point of view, in the light of Bahtin’s theory of speech genres, school textbooks are seen as a specific, complex genre, defined by the addressee. At the same time, this approach requires us to see textbooks as a cultural product. From an educational point of view, textbooks are, according to Vygotsky’s theory of cultural development, a key socio-cultural aid to cognitive development in school years. Forty-three quality standards are operationally defined and explained. They can be used for compiling textbooks, for textbook accreditations, for textbook evaluation and for selection by teachers.