ABSTRACT
On many accounts, the twentieth century has witnessed an unprecedented transformation of the world. Economic growth, technological innovation, the shrinking of the world due to the emergence of modern means of transport and of communication, the globalization of the economy, sometimes of politics, two world wars and the multiplication of regional conflicts, are among the many phenomena of historical dimension that have reshaped the world during this century. And undeniably, the increase in the number of persons living on Earth is another facet of this profound transformation.
