In recent years national and international reports have been issued that speak of the sad state of the educational system in the United States and the desperate need for reform in teaching science and mathematics. Cognitive psychologists and mathematics and science educators have responded to this need by designing instructional programs that are more compatible with our knowledge of how people acquire, use, and retain knowledge. Many of the guiding principles that underlie these programs are presented in this volume such as teaching comprehension of scientific text through a problem-solving approach: problem planning and representation, selection of relevant information, and simultaneous monitoring of both the specifics of the problem and the mental processes being used to solve it.