"Science Education and Curricula in Twenty-Three Countries" is the first in a series of three volumes presenting the results of the second IEA Science Study. Comparisons are made between countries in terms of the conditions under which science is taught, the organization of science teaching, the emphasis on different science content areas and on the process of science, the focus of decision-making with respect to the science curriculum, and the penetration of new ideas in science teaching. Consideration is also given to the fair and valid assessment of science education across countries. Reports on the provision of science education in each country studied are included.