This book presents 13 essays written by teachers working with constructivist methods and principles to transform their own mathematics instruction, largely along the lines of the NCTM Standrads. Bringing readers into their classrooms to "see" and "hear" for themselves, these teachers detail their successes and failures as they proceed, with guidance, to reshape the teaching and learning process. the papers in this book are quite varied. Some explore particular grade-specific mathematical topics--third graders investigating multiplicative commutativity, sixth graders using Logo to discover properties of triangles, high school students constructing meaning for the concept of variable. In contrast to traditional presentations, these papers contextualize such activities in the life-process of particular classrooms.
Looking for something secondary education related, I loved the constructivist bent. Although dated (1996), reform-minded teachers pose problems and encourage students to think deeply about possible solutions. They promote making connections to other ideas within mathematics and other disciplines. They ask students to furnish proof or explanations for their work. They use different representations of mathematical ideas to foster students' greater understanding. These teachers ask students to explain the mathematics. Even at an elementary level, this was a good read. Recommend to my elementary school teacher friends.