Urbanization is the physical growth of urban areas as a result of rural migration and even suburban concentration into cities, particularly the very largest ones. The United Nations projected that half of the world's population would live in urban areas at the end of 2008. By 2050 it is predicted that 64.1% and 85.9% of the developing and developed world respectively will be urbanised.
- Quotes are arranged chronologically
20th century, first half 
- Cities are, first of all, seats of the highest economic division of labor. They produce thereby such extreme phenomena as in Paris the remunerative occupation of the quatorzième. They are persons who identify themselves by signs on their residences and who are ready at the dinner hour in correct attire, so that they can be quickly called upon if a dinner party should consist of thirteen persons. In the measure of its expansion, the city offers more and more the decisive conditions of the division of labor. It offers a circle which through its size can absorb a highly diverse variety of services.
- Georg Simmel (1903) The Metropolis and Modern Life p.420
- Make no little plans; they have no magic to stir men's blood and probably themselves will not be realized. Make big plans; aim high in hope and work, remembering that a noble, logical diagram once recorded will not die, but long after we are gone be a living thing, asserting itself with ever-growing insistence. Remember that our sons and our grandsons are going to do things that would stagger us. Let your watchword be order and your beacon beauty.
- Daniel Burnham (1921) in: Daniel H. Burnham, Architect, Planner of Cities by Charles Moore. Boston, Houghton Mifflin; Volume 2; Chapter XXV "Closing in 1911-1912;" Page 1921.
- To be in good moral condition requires at least as much training as to be in good physical condition. But that certainly does not mean asceticism or self-mortification. Nor do I appreciate in the least the idealization of the "simple peasant life." I have almost a horror of it, and instead of submitting to it myself I want to drag out even the peasantry from it, not to urbanization, but to the spread of urban cultural facilities to rural areas.
- Jawaharlal Nehru (1936) Autobiography, p. 315
20th century, second half 
- Now this problem of the adjustment of man to his natural resources, and the problem of how such things as industrialization and urbanization can be accepted without destroying the traditional values of a civilization and corrupting the inner vitality of its life — these things are not only the problems of America; they are the problems of men everywhere. To the extent that we Americans become able to show that we are aware of these problems, and that we are approaching them with coherent and effective ideas of our own which we have the courage to put into effect in our own lives, to that extent a new dimension will come into our relations with the peoples beyond our borders, to that extent, in fact, the dreams of these earlier generations of Americans who saw us as leaders and helpers to the peoples of the world at large will begin to take on flesh and reality.
- George F. Kennan (1954) Lecture at Princeton University, Princeton, New Jersey (March 1954); published in “The Unifying Factor” in Realities of American Foreign Policy, p. 116
- "Urban problems" are increasingly becoming a political issue as the socialization of the means of production is accompanied by the increasing socialization of the means of consumption or, if one prefers, from the moment collective facilities begin to play a strategic role in the structure and rhythms of everyday life.
- Manuel Castells (1972) Urban renewal and social conflict in Paris p.93
- To consider the city as the projection of society on space is both an indispensible starting point and too elementary an approach. For, although one must go beyond the empiricism of geographical description, one runs the very great risk of imagining space as a white page on which the actions of groups and institutions are inscribed, without encountering any other obstacle than the trace of past generations. This is tantamount to conceiving of nature as entirely fashioned by culture, whereas the whole social problematic is born by the indissoluble union of these two terms, through the dialectical process by which a particular biological species (particularly because divided into classes) "man", transforms himself and transforms his struggle for life and for the appropriation of the product of his labour.
- Manuel Castells (1977) The Urban Question: A Marxist Approach p.115
- Could it be argued that if the Chinese revolution seems to be a response to the needs of rural society, whereas the Russian is an urbanized phenomenon, this difference corresponds to that which exists between the users of two different forms of written communication, the one archaic, the other alphabetic?
- Eric A. Havelock (1987) "Chinese Characters and the Greek Alphabet" in Sino-Platonic Papers, 5 (December 1987)
- Urbanization is the advent of edge species.
- Kevin Kelly (1995) Out of Control: The New Biology of Machines, Social Systems and the Economic World
21th century 
- One of the first theorists to acknowledge the deep and important impact of urbanization on social life was the German scholar, Georg Simmel. Simmel developed a sociology that focused on the special ways that forms, such as the number of people in groups, influenced social life. His effort to understand the nature of urbanization and, in particular, the metropolis of the late nineteenth and early twentieth centuries, displayed his characteristic method of analysis.
- George Ritzer (2004) Encyclopedia of Social Theory. Vol.1-2. p.854
- Some economically brilliant groups of this kind have behind them a long tradition of dispersal, urbanization and minority status: this is clearly the case of the Jews, Greeks, Armenians or Parsees.
- Ernest Gellner (2006) Nations and Nationalism (New Perspectives on the Past) Blackwell Publishing Limited. p.101
- The accumulation of capital and misery go hand in hand, concentrated in space.
- David Harvey (2006) The Limits To Capital. 2006 VERSO Edition. p.418