Buildings are our third skin. To survive we need shelter from the elements using three skins. The first is provided by our own skin, the second by a layer of clothes and the third is the building. The more extreme the climate, the more we have to rely on the building to protect us from the elements. This book is about how climatically responsive design within dwellings in Egypt can meet the requirements of its users and improve the quality of their life. It also concerns with the climatic data available for all climatic design regions in Egypt and how it can be obtained. It deals with important point which does not take efforts from researchers till this moment, which is the appropriate way of use of this climatic data by an advanced computer program on energy performance of buildings to take a decision in the different stages of climatic design. The book is also exposed to all different trials to dividing Egypt into climatic design regions and put imagination on new climatic design classification of Egypt according to all these attempts.