I. THE SUBJECT Our definition of the subject will be the use of economic analysis to understand the economies of poor or developing countries. This includes, in particular, how standards of living in the population are determined, and how they change over time, and further how policy can or should be used in the influence of these processes. The definition contains, in principle, much or most of analytical methods in economics insofar as they can be put to use in the examination of the issues of interest. This is as it should be but it poses a problem for a survey in a journal. A comprehensive treatment is infeasible so we shall follow a different route. The survey will focus on what I take to be the major themes and approaches which characterise the productive aspects of the subject. There is, therefore, no pretence at being exhaustive. The purpose is rather to highlight some of the advances. Many of these have been of real substance. There are a number of possible purposes for a survey and it is important to be clear at the outset for whom it is intended, what it is, and what it is not. This survey is addressed to economists and students of economics who .know the tools of their trade but not necessarily how they have been applied to, and fashioned for, the analysis of the economics of developing countries. It is a description of the ways in which problems can be productively formulated and approached, in terms of examples chosen for their intrinsic importance and interest. The vastness of the subject means that we have to be highly selective. It does not seek to provide a summary evaluation of the current view of the 'appropriate' response to immediate policy questions. It is not a history of thought, nor a research manifesto nor an attempt to adjudicate or settle the major debates. Where they arise naturally from the major purpose some judgements on these subjects will be offered, but they do not themselves constitute the primary intent of this survey. There are three lines of enquiry, or sets of questions, which have, I suggest, been distinctive of the most fruitful work in development economics. They will