Twelve chapters describe an 18-nation study of educational attainment at the elementary and secondary school levels. Professional researchers participated in the project, developed through UNESCO and conducted under the auspices of educational research centers in Australia, Belgium, Chile, England, the Federal Republic of Germany, Finland, France, India, Iran, Italy, Japan, the Netherlands, New Zealand, Poland, Scotland, Sweden, Thailand, and the United States. Subjects of the chapters include: Testing of achievement in science; reading comprehension; literature; French as a second language; English as a second language; civic education; development of measuring instruments; hypotheses, sampling designs, and between country analyses; plans for data collection; processing procedures; and consequences of IEA studies on education research and policy decisions. Ten appendices include proposals for future IEA work and basic testing rationales. (An expanded and revised version of Appendix F-1 appears as ED 018 431.) Related documents are Volume II, sections 1-4 and 6, (EA 002 615) and Volume II, section 5, (FL001 477). (JK)