The Twentieth-Century Historic Thematic Framework: A Tool for Assessing Heritage Places promotes broad thinking about the historical processes that have contributed to the twentieth-century built environment worldwide. It identifies and analyzes the principal social, technological, political, and economic drivers that have shaped the buildings, cities, industries and landscapes of the twentieth century, emphasizing global forces, trends, and phenomena that have shaped the built environment. The Framework uses ten succinct themes to organize and define history, helping to identify heritage sites and place them in context: 1. Rapid Urbanization and the Growth of Large Cities 2. Accelerated Scientific and Technological Development 3. Mechanized and Industrialized Agriculture 4. World Trade and Global Corporations 5. Transportation Systems and Mass Communication 6. Internationalization, New Nation-States, and Human Rights 7. Conserving the Natural Environment, Buildings, and Landscapes 8. Popular Culture and Tourism 9. Religious, Educational, and Cultural Institutions 10. War and its Aftermath Beginning with an overview of the themes, subthemes, and places that exemplify them, readers can quickly navigate to any one theme that is of particular importance to their area of research. Each section concludes with a photo gallery showing a diverse range of buildings, sites, structures, and landscapes that illustrate the issues discussed. Although globally structured, this framework can be used locally to survey and assess places within the context of the twentieth century and to conduct comparative analyses of places. It can be utilized and adapted by anyone involved in heritage conservation around the world. Our hope is that it will aid many forms of research, analysis, and survey work, and ultimately help sustain and conserve the heritage of the twentieth century. Commissioned by the Getty Conservation Institute (GCI) working in collaboration with the ICOMOS Twentieth-Century Heritage International Scientific Committee, this publication is an outcome of the Conserving Modern Architecture Initiative.