A bonus of Volume II is Plott's appendix on "The Problem of Periodization," a fifty-page essay done in collaboration with Michael Dolin and Paul Mays. Mays has also provided a superb annotated map and time-line of "The Han-Hellenistic- Bactrian World" which rides in a pocket of the volume jacket.

"The Problem of Periodization" is too modest a title, since the essay offers a proposal by which the problem can be tentatively resolved. Plott and his team identify clusters of more or less contemporaneous events around the world to mark off significant transitions and boundaries for the periods. The specific continuity between turning points is identified by the events and achievements that provide the "body" for each period. Because the Plott team has had to discuss both the continuities and the turning points of history in their essay, it becomes an outline of world history, both general and intellectual, extending right into our own times. This is fortunate as it allows us to glimpse how the project would have been organized and presented in the volumes that never got published. But the chief virtue of the essay on periodization is that it provides us with a means of delimiting and characterizing periods historically and logically instead of by mere ethnocentric scholarly tradition.

Plott emphasized the imperfections and tentativeness of his periodizations. Wallace Gray is more sanguine about what Plott, Mays, and Dolin accomplished in their essay. "It is one long critique of the many scholarly efforts (including Plott's) to periodize area and world history. As a result of the careful critique, they succeed in avoiding many of the pitfalls the essay names."

These findings and proposals on the periodization of world history are applicable to some recent histories such as the single-volume 1992 Histoire de l'Europe, produced by the cooperative effort of twelve scholars from as many countries (published by Hachette in Paris under the direction of Frederic Delouche). Plott would appreciate the wonderful maps and other graphics in this volume. He would be critical of the usage, though perhaps necessary, of such cliched terms as "medieval" and "Renaissance," but he would affirm the long-time perspective with which the volume opens: "From the tundra to the temple (Prehistory to 4th century B.C.)" and the wide, truly global space-perspective indicated by one map caption which roughly translates, "Europe, the peninsula of Asia." In such contexts Plott prefers the term "Eurasia" which the authors of Histoire de l'Europe use in the heading for the section beginning at this same map, a map by the way which suggests the earth as seen from the moon more than the old-fashioned "flat" Mercator projections. Since the philosophy of historical periodization which Plott and team have developed is especially severe in criticisms of the arbitrariness of much traditional period-naming, the comment from the Preface of Histoire de l'Europe is apropos. A 19th- century writer is quoted: "God, although he is omnipotent, cannot change the past. So he created the historians." Incidentally, the English version of this history is available from Henry Holt (New York: 1993).