The field of vernacular architecture offers an abundance of concepts that can be of use today in solving the critical housing situation now facing millions in the Third World. The example chosen to illustrate this by the UNU Energy Subprogramme covers the vernacular architecture of the hot, arid zones of the Arab World and neighboring regions. It was felt that the person best suited to prepare a monograph on this subject was Professor Hassan Fathy. Not only is Professor Fathy a master architect and an expert in the area of traditional architecture, especially in the Arab World, but he has been so for more than half a century. His work has also demonstrated the value that traditional architecture can have in improving the housing and living environments of the poor of the Third World. As a theoretician and practitioner of environmental planning design, Dr. Fathy's approach is based on a set of principles that are useful in opening the mind to the value of vernacular architecture and to adapting it to the situation in which a large fraction of the world's population find themselves today. Professor Fathy's approach is based on the concept that architectural form should be determined by spiritual, artistic, climatic, and social considerations as well as function, material, and structure. He emphasizes that due consideration must be given to a number of elements including harmony. -- from Foreword.