This publication presents general principles and methodologies that are applicable across sectors, including quantitative risk analysis. It provides both theory and practice about how to evaluate transportation, health, and education projects; and explains how to assess the environmental impact of projects. It provides a fresh look at the tools of project analysis and explains how to apply quantitative analysis of costs and benefits from multiple perspectives-- including the private sector, the public sector, bankers, and the country as a whole. The examples used to illustrate the principles are drawn from actual projects of the World Bank and other institutions.