The whole world is moving towards a more urban existence and whereas the process is more nearly completed in the small number of rich industrialized countries, it is only in recent years that marked urbanization has started making its impact over the less-developed countries. Increased urbanization is now occurring throughout the Third World, unfortunately, however, at a pace far in excess of the economic advances and the Third World is now undergoing a great urban crisis. A number of large cities have trebled in size in past decade, and many others, including Delhi, have doubled. The increase in illegal housing in these rapidly expanding cities has assumed even more dramatic proportions and in many cases squatter populations are increasing at twice the overall rate of urbanization. More than half of the populations of many larger cities in Africa. Latin America and Asia now live in unauthorized settlements, as do more than a quarter of populations of places as divers as for example, Mexico City, Rio de Janeiro, Calcutta and Seoul. The situation calls for new solutions increasingly based on a deeper understanding of social and economic requirement and practicalities and less on unsupportable idealism. The coverage includes, besides introduction, urban squatter problems in Third World, approaches followed by different countries of the World, and approaches being followed in India. Delhi has been taken as a case study and the impact of the policies in Delhi has been evaluated. The lessons and experiences of other Third World countries have been drawn to indicate the various problems and their solutions and also other important issues which should be considered while formulating resettlement policies for the squatters. On the basis of his wide experience and positions of responsibility held by him in Delhi and elsewhere, Dr. Basu has made an important study which will go far towards improving the understanding of squatter resettlement requirements and policies applicable to the burgeoning cities of the Third World.