The past is not simply a list of events.  Historical records are the means by which historians develop their interpretations of those events. Because interpretations differ, there is no single historical record, but various narrations of events each told from a different perspective. Therefore the study of history is intimately linked to the study of values, the values of the historical actors, the historians who have written about them, and of the students engaged in learning about them.   The World's History links chronology, themes, and geography in eight units, or Parts, of study.  The Parts move progressively along a time line from the emergence of early humans to the present day. Each Part emphasizes a single theme--for example, urbanization or religion or migration--and students learn to use them all to analyze historical events and to develop a grasp of the chronology of human development.   The final chapter employs all the themes developed in the first seven Parts as tools for understanding the history of our own times. Geographically, each Part covers the entire globe, although specific topics place greater emphasis on specific regions.