This chapter discusses the art of teaching and the role of the teacher in presenting tasks, establishing an inviting classroom environment, and leading classroom discourse that challenges and sparks interest in the students. It deals with a discussion of the NCTM Standards for Teaching and Learning Mathematics and the related principles from Principles to Actions: Ensuring Mathematical Success for All. Teachers themselves need to have a sound content knowledge, as well as a deep understanding of the psychological, social, and cultural factors that influence the teaching and learning process. The teaching and learning principle expresses the common theme of meeting students “where they are” and making lessons meaningful, relevant, and challenging. Principles to Actions emphasizes the importance of the caring teacher in promoting the teaching and learning of mathematics for all students. Of course, students’ willingness to engage in rich tasks and to take risks depends on the climate that has been established in the classroom—the learning environment.