This set of materials is comprised of eight, one-hour videotapes and an accompanying 171-page workshop guide that provide a series of activities for a professional development workshop. These materials are designed to be used with middle school mathematics teachers to explore specific topics in the middle school mathematics curriculum.

The purpose of these materials is to "help close the gap between where we are and where we need to be" regarding helping middle school students learn the mathematics they need for success in the 21st century (p. 1). The materials are designed for professional development providers to use to help middle school mathematics teachers "better understand the content of four important topics rarely taught to American middle school students," and "improve their instruction through engaging problems that involve students in their own learning" (p. 1).

The Missing Link is a complete, well-designed professional development program for middle school mathematics teachers that explores four mathematical topics: proportionality and similar figures, patterns and functions, polygons and angles, and sampling and probability. Each of these four topics in the workshop series is divided into two parts. The first part engages teacher participants in an exploratory and learning phase, and the second, follow-up session examines results after the teachers try the lessons in their own classrooms. Middle school teachers from several schools in various states participate in videotaped demonstration workshops that are led by an award-winning middle school teacher. In these workshops, the "learner teachers" participate in hands-on problems, then watch videotaped sessions of the master teacher helping her own middle school students with the same problems. Three months later, the teachers discuss their experiences as they tried the problems with their students.

All the demonstration teacher workshops were videotaped and those videotapes form the basis of the series of materials. They offer well-organized and clear examples of how professional developers can guide middle school mathematics teachers in their efforts to revise their teaching techniques and employ a student-centered, exploratory approach to learning in the classroom. The videotaped lessons follow the format of "Launch," aimed at hooking the students into the topic, "Explore," where students investigate a problem and teachers listen and observe, and "Summarize," where students discuss to provide clarity about the main idea of the lesson.

A detailed workshop guide accompanies the videotapes and provides suggested agendas and more detailed plans for two workshops on each of the four mathematical topics. Worksheets and transparency masters are included to support each session along with directions on how to proceed and samples of the types of questions to ask. For each workshop, the authors suggest how to organize a two- or four-hour workshop, but professional development providers are encouraged to implement the longer versions so teachers will have time to do the lessons themselves and have more extended conversations with their colleagues.

These materials are specifically designed for professional development that addresses not only mathematics content, but also instruction and assessment. Reviewers suggested that utilizing the same problems as those in the videotapes, professional developers could duplicate the design of the workshops by offering an introductory series of lessons followed by classroom trials and a return session for assessment and further discussion. The videotapes could be viewed by the professional development participants, but could also be used in advance by the professional development provider as a rich guide to planning the workshops. The workshop guide also provides detailed outlines that are of great value for the workshop leader.

To help teachers from becoming isolated as they implement these lessons, additional resources are available. The Annenberg/CPB website http://www.learner.org/channel/workshops/missinglink offers a discussion forum specifically for Missing Link participants, as well as other information related to these materials. Participants are encouraged to share and pose questions about the workshop series, get to know their colleagues, and ask questions about technical access issues.