The pressure exerted on cities in recent decades is extremely evident. There is no need for one to consult official statistics to realize that cities are turning into the place where most of the population prefers to live and work. Residing downtown or in inner city areas, where business and cultural activities are to be found, is very practical and with more advantages than those that were to be had in suburban areas only a few years ago. Employment is also concentrated in urban areas, and this explains the progressive population decline in rural areas of developed countries. "High Density Housing Architecture" shows different types of multi-residential buildings situated in urban centers as a metaphor for the growing overcrowding of cities and for what some call the 'new global lifestyle'. These pages document some twenty-five low and high density residential projects in cities such as Istanbul, New York, Tokyo, Mexico City and Sydney.