The authors used as primary data for the project the published proceedings of every International Congress, the minutes of its assemblies, and of the meetings of the various executive committees. As a result, it is rich in detail that would otherwise be very difficult to trace in the archives of the Union. In the appendices, for example, lists of the membership of the International Congress of Psychology Committees from 1889 to 1951 appear, as well as its office bearers since 1951, together with a copy of the "Statutes and Rules of Procedure of the IUPsyS". Indeed, there is so much detail in here that the book may almost act like a primary source itself for future researchers. (One casual observation struck me: between 1889 and 2000, only 2 of its 27 International Congresses were held in the United States -despite the U.S.'s dominance of psychology around the world).
The book thus is both a history and a commemorative description of events. As a descriptive narrative of what happened between 1889 and 2000, it works well. Also, because it is a commemoration, it contains respectful references like "very successful in fulfilling their mission," "sustained focus on its priorities," "played a constructive role," "genuine global expansion," and so on.
As history, however, it fares less well, mainly because there is virtually no historical analysis presented. That may or may not be an unfair expectation of a book like this, but even if one does not expect some analytical effort, the way the material is presented does not make for easy reading. It is so rigorously chronological, and so relentlessly descriptive, that it is nearly impossible to read it like one would normally read a book. I suspect readers might use it either to confirm or look up dates, persons, and events, or to dip into now and again to look for nuggets of interest.
At the very least, I would have liked the authors to be a little less celebratory about "a genuine global expansion of international psychology" (p. 195), as the International Congresses held in Asia (1972), Latin America (1984), and Australia (1988) signified the export of psychology to the non-Western world. The enthusiasm for being truly global and promoting the growth of psychology internationally can be juxtaposed with the post-War and Cold War social and intellectual context within which this took place. It was in exactly this context that strong political support existed for establishing international scientific organizations. Indeed, in chapter 2 the authors allude to the renewed scientific communication between the former foes after World War II, and the establishment of new international unions, linked to UNESCO. This is just one of the instances where I thought the authors missed an opportunity to reflect more on what all of these developments mean in a slightly wider context.