portion of the TIMSS 1999 Video Study included Australia, the Czech Republic, Hong Kong SAR, Japan, the Netherlands, Switzerland, and the United States. In this article, we focus on the mathematics lessons; the science results will be available at a later date. Stimulated by a summary article that appeared in the Kappan and by other reports, interest in the TIMSS 1995 Video Study focused on its novel methodology and the striking differences in teaching found in the participating countries. In particular, the sample of eighth-grade Understanding and Improving Mathematics Teaching: Highlights from the TIMSS 1999 Video Study