Broadly speaking, the aim of this book on slum up gradation is to draw some conclusions for the formulation of policies. Several chapters therefore present descriptive material from each case study relevant to the topic concerned. Although each of the chapters concentrates on a particular aspect of slum and squatter settlement, it is the interaction of these various aspects that characterizes a settlement. In particular, the pattern of change over time shows the factors at work in shaping the settlement and the lives of its inhabitants. This book would accurately portray the conditions of life in slum and squatter settlements and, in particular, show how the authorities and the residents deal with their problems. No systematic review of government policies for slum and squatter settlements is presented here. However, in analyzing the implications of the case studies, it is necessary to situate the findings against a background of possible policy and technical alternative. The usual range of policy options includes sites-and-services schemes, squatter upgrading, aided self-help, relocation and other variants of settlements policy for low-income groups. It is hoped that the data and descriptions included in the Book will prove useful and that overall knowledge of conditions in slum and squatter settlements will be enhanced. It cannot be claimed that the data are comprehensive; they simply show what was happening in the mid-1970s in particular places on three different continents. Much will have changed since then, even in the settlements studied, for low-income settlements change rapidly under the pressures of population growth, migration and urban family formation, as well as the actions of squatters, authorities and the informal sector in response to such pressures. It should also be borne in mind that resources for data collection were limited and that little accurate information had been collected previously. It is the purpose of this Book to serve as a source of reference and information for policy-makers and other persons involved in finding solutions to these fast-growing problems. This book addresses itself equally to persons and institutions in both developing and industrialised countries. It is hoped that a comparative analysis of this nature will assist the Governments of developing countries in their efforts to find appropriate policy approaches through information exchange. It is also hoped that agencies and institutions in industrialized countries which are extending aid to the developing world wil find it useful to receive inputs for the formulation of their aid policies and the identification of the type of assistance programmes needed. The picture presented in this book is an image not only of a particular point in time but also of ongoing processes. The conclusions that are drawn are perhaps not the only one possible. The data are rich in their complexity and have been presented in the hope that others may draw on them in other ways and for other purposes. The result of the case studies is thus an image of ongoing life in slum and squatter settlements, an idea of some of the ways squatters and authorities attempt to cope with their problems and a partial critique of what this implies for existing policies.