As this book's subtitle indicates, it will examine many of the main twentieth-century global forces, which often clashed with one another. This work also attempts to present different, also often conflicting, viewpoints about these forces. And the question mark in the book's title (An Age of Progress?) suggests that contending judgments exist as to whether the century was one of overall progress. Thus, the following pages are more of an analysis and assessment of the century than an introduction to it, and are intended for students or general readers who already possess a basic knowledge of it. A rough draft of this manuscript was used in an advanced team-taught undergraduate seminar in the winter of 2007, and it stimulated much healthy debate.

As with any work dealing with twentieth-century global history, this work is limited and selective. It deals with some, but not all, of the important trends of the century. Within these trends, it concentrates more on developments within the more industrialized world of western Europe, the United States, and Russia/USSR than on those in the less industrially developed parts of the world.

There are two reasons for the relative neglect of areas outside of the industrialized West and Russia. First, except for Russian history, which I have taught and written about for many years, my knowledge of non-Western countries is simply too limited to do more than mention some ways that my main trends interacted with them.