The talk will give an overview of the role of examples in mathematical thinking, learning, and teaching. It will elaborate on findings from a three-year study examining how secondary mathematics teachers select, construct, and use examples in their classrooms. The main purpose of the study was to characterize some aspects of teachers' use of instructional examples as well as their underlying considerations. In addition, the notion of example-space will be introduced, the kind of knowledge that is needed for judicious choice of examples will be discussed, and {\it a mathematics example-related teaching cycle} that accounts for ways in which teachers use examples in and for their classrooms will be presented. Presented by UCSD and SDSU Mathematics and Science Education Joint Doctoral Program (MSED)