In this book, the author presents a new vision of learning through design and production, and describes computer programming as a source of a learning and design power. As means of studying this extended notion of children's programming, the author implemented Instructional Software Design Projects to explore the learning that takes place when students develop complete mathematical software products designed for other students in their school. The results demonstrate that the young designers learned not only about mathematics (fractions) and programming (Logo), but also about design and user interfaces, as well as representational, pedagogical, and communicational issues.