Abstract: 

The present study deals with the textbook considering it as one of the most important enculturated enacting media for the development of the teacher-intended curriculum, which incorporates the beliefs, interpretations, decisions, and actions that teachers make in order to envision, schedule, plan, design, and implement instruction in the natural contexts (institutionalised classrooms). This is a quantitative study, which elaborates a sample of sixty-seven (67) Greek secondary mathematics teachers, who responded to an issued to them structured questionnaire. The questionnaire was specifically and appropriately designed to glean the teachers' judgements concerning the content of the textbooks, the curriculum materials, and resources in use, as well as the way they use them for scheduling, planning, and implementing their instruction according to the officially established curriculum. The methods of the descriptive statistics are used in order appropriate inferences to be drawn. Recommendations are given concerning the state of the used mathematical textbooks in Greece as the means for enacting the sanctioned curriculum, the improvement of the teachers' instructional practices, and for the subversion of specific misconceptions (Lousis, 2017) in the students' mind, which are probably due to the enactment of the sanctioned curriculum via textbooks and have an international existence and perspective.