In 1965 the International Association for the Evaluation of Educational Achievement (IEA) inaugurated a cross-national survey of achievement in six subjects: Science, Reading Comprehension, Literature, English as a Foreign Language, French as a Foreign Language, and Civic Education. The overall aim of the project was to use international tests in order to relate student achievement and attitudes to instructional, social, and economic factors, and from the results to establish generalizations of value to policy makers worldwide. Contained here are 22 Science tests measuring achievement in the following areas and for the following student populations: General Science (population I, II, IV); Advanced Science (population IV); Specialist Biology, Chemistry and Physics (population IVS); Practical Science (population II); Practical Science, Biology, Chemistry, and Physics (population IV); and Understanding the Nature of Science (populations II, IV). Population I consists of students aged 10 to 11 years; population II, 14 to 15 years; population IV, students enrolled in the final year of pre-university training; and population IVS, those students in population IV specializing in Science. Answer keys and statistical data can be found in ED 081 639. (RC)