For over 30 years now large-scale investment has been made in science education throughout the world and in developing countries in particular. A handful of countries have indeed succeeded in raising their respective population's general level of scientific knowledge, but in other countries, in spite of much effort, the shortage in supply of science-trained students persists, examination achievement levels remain low, and the cost of provision so high that many children all over the world are denied access to effective science teaching. Whilst the problems of curriculum relevance have been widely discussed, little attention has been paid to the issues confronting the policy-maker and the manager in deciding how much to invest in science education, how to provide value for money or how much science to provide for how many students. This book addresses the question of how best to plan investment in science at secondary level in developing countries using insights from the studies conducted under a five-year research programme carried out by the International Institute for Educational Planning. The result is an extensive account, commentary and analysis of the main issues that the planners of science education in developing countries are likely to be confronted with when addressing the challenges of the twenty-first century.