Results from the Third International Mathematics and Science Study (TIMMS) have recently captured the attention of the United States and once again focused the nation on matters of mathematics teaching and learning. In general, the TIMSS results indicate a pervasive and intolerable mediocrity in mathematics teaching and learning in the middle grades and beyond. At Grades 7 and 8 and also at Grade 12, U.S. students achieve poorly in mathematics compared to students in much of the rest of the world. Even the 12th-grade students who take advanced mathematics courses performed substantially below students in most other nations. The results also suggest that the demands made by the U.S. school mathematics curriculum and mathematics classroom instruction are not as challenging as in other countries. This document reports the major findings from TIMMS and makes some recommendations for enhancing mathematics teaching and learning in the middle grades. Contains 40 references. (ASK)