This publication, written for citizens and professional educators, releases about 40 percent of the data describing what groups of Americans know and can do in the area of science. Nine-year old elementary (28,000), thirteen-year old junior high (28,000), and senior high students were tested. In addition 10,000 adults, ages 26-35, were involved. Four major objectives assessed included: (1) Fundamental Facts and Principles of Science, (2) Abilities and Skills Needed to Engage in the Process of Science, (3) Understanding the Nature of Science, Attitudes and Appreciations of Scientists, Science, and (4) the Consequences of Science that Stem from Adequate Understandings. Data were analyzed to yield information regarding: (1) four geographic regions, (2) four sizes of communities, (3) four types of communities, (4) sex, and (5) levels of parents education. Appendices include the development of the National Assessment Exercises, Definition of Terms, Structure of Sampling and Weighting, and Data for Nine Selected Science Exercises. There is no attempt in this report to discuss whether these results show that the status of science education and knowledge in the United States is good or bad, or to make recommendations on the basis of these results. (BB) Primary type of information provided by report: Assessment Instrument (Released Exercises); Results (Exercise Level).