This innovative new text from Jeffrey Sachs and Xiokai Yang introduces students to development economics from the perspectives of inframarginal analysis and marginal analysis. The book demonstrates how the new-found emphasis on inframarginal analysis has influenced a shift back to an interest in Classical Economics from Neoclassical Economics. * Inframarginal Analysis vs. Marginal Analysis is presented as a consistent theoretical framework throughout. * Shows how the relationship of Inframarginal Analysis to Marginal Analysis has influenced the shift back to an interest in Classical Economics from Neoclassical Economics with regard to economic development. * Allows economists to reduce their overall reliance on marginal analysis, which may be less relevant to development economics than it is to the economics of development countries. * Brings considerable analytic machinery to bear on important problems. * A focus on institutions and transaction costs that is very relevant to development economics. * Offers a thorough analysis of trade (CHs. 3 - 7) and macroeconomics (CHs. 16 - 19), both of which are not dealth with in depth by comparable textbooks.