The 20th century has been a remarkable age of material advancement and sociopolitical transformation. In all parts of the world, people have witnessed profound changes in their conditions of life: infant mortality rates and adult illiteracy have dropped as dramatically as primary school enrollment and life expectancy have increased. Nevertheless, despite unprecedented material progress, basic education, health care, housing, and social protection remain insufficient for the majority of the world's population. In developed and developing countries alike, governments are re-evaluating their social policies, programs, and safety nets. They are experimenting with various approaches, including altered principles and procedures for social-service financing and shifting divisions of responsibility for the state, the private sector, and nongovernmental actors.