Cases, while always interesting to read, are more effective when discussed under the guidance of a skillful leader. Because many educators are new to the case method of instruction, particularly in the subject area of secondary mathematics, this facilitator's guide is an essential companion to Windows on Teaching Math: Cases of Middle and Secondary Classrooms. In this guide, Katherine Merseth provides specific teaching notes that correspond to each case, helping educators to successfully use Windows on Teaching Math in a teacher education course or professional development workshop.