Since 1985, "Advances in Special Education" has aspired to advance theories and best practices essential to understanding, treating, and instructing students with disabilities. At times, advancement involves vision and innovation. At other times, new technologies, cutting edge medical procedures, or innovate pedagogical practices capture the attention of special education professionals globally and substantial changes can result in the way students with special needs are instructed. This volume in "Special Education International Perspectives" invites a call for common ground and global commonalities in all schools. The main theme of this chapter is that teachers matter. The chapter reviews two decade of scientific evidence that supports this theme. The scientific evidence comes from neuroscience and social cognition findings related to the importance of the teacher-student interaction. Environmental influences are not only the physical world but the all-important social world. The chapter begins with an overview of the "social" brain relative to teaching. A practical guide for teacher use of evidence-based educational practices concludes the chapter. [For the complete volume, "Special Education International Perspectives: Biopsychosocial, Cultural, and Disability Aspects. Advances in Special Education. Volume 27," see ED592774.]