More than most other historical sub-disciplines, intelligence history can be a frustrating endeavor because of the pervasive classification of primary source materials. Yet, even though in many countries, not least the open societies of the West, government agencies continue to hold back or to sanitize far too many documents from the Cold War era, historians have in recent years gained access to new collections and papers. As Douglas MacDonald suggested recently, compared to the situation during his graduate student days in the 1970s, the glass today can be seen as half full.

Newly available, albeit still incomplete, archival collections are one reason for Keith Allen's book; the suitability of Cold War Germany for the study of the activities of intelligence agencies is another. A third reason offered by Allen is continuity. After 1990 Western intelligence services sought to learn about the networks of people who moved to and through the Federal Republic of Germany (FRG) during the Cold War. How did these activities affect the lives and personal freedoms of what often were vulnerable migrants? How did the activities of (especially) British and U.S. intelligence services, present in the country by virtue of their role as occupying powers after World War II, affect the sovereignty of the FRG? How did West German agencies cooperate with their Western counterparts active on their soil?

Allen, a research scholar at the Institute for Contemporary History in Berlin, has done a large amount of research in U.S., British, and German archives (supplemented by work with declassified East German State Security, or Stasi, and Czechoslovak State Security files) in order to map the geography, methods, and human impact of the interrogation of the hundreds of thousands of people who entered West Germany from the East during the 1945–1989 period. The complexity of the subject is suggested by the glossary of abbreviations stretching over nearly five pages. Readers may at times find it hard to keep track of the various U.S., British, and West German organizations involved (French activities have been largely left out because of the lack of access to relevant collections in French archives and the apparently secondary role the French played here), to say nothing of the vast network of locations for interrogations of migrants.

Even though many collections now yield useful information, the record is far from complete, something Allen is meticulous in pointing out throughout his account. At the same time, he believes that serious study of the machinery of migrant interrogation can now be attempted on the basis of primary documents, which is why he has steered clear from adding to the record through oral history interviews. This is a defendable position insofar as oral history has significant pitfalls, but one wonders whether his decision to forgo this venue has deprived him of additional information or insights.

The book is organized thematically, first mapping the “places” where interrogation took place, next tracing some of the personal experiences of those in the crosshairs of Western services (“personalities”), and finally focusing on the methods, or “practices,” used by the interrogators. This way of organizing the material makes sense in light of the complexity of the subject, but it gives much of the book the character of an inventory of what can be found in the respective archival collections, often presented in short sections, supplemented with examples from the interrogation practice. The account is rich in information, but it does not always cohere in a satisfying way.

The thematic focus on the nuts and bolts of the interrogation infrastructure and practice also comes at the expense of context. The Cold War is not wholly absent, but reading the book one can sometimes lose sight of what migrant interrogation was meant to achieve (primarily, but certainly not limited to, the gathering of information on the Soviet order of battle in East-Central Europe, we are told). The Cold War is referred to as “the global battle of national security ideologies” (p. 62), as “the era of clashing ideologies” (p. 95), and as “the American-led global struggle against Soviet hegemony” (p. 192). On p. 25 we read about the “Sino-Soviet invasion of South Korea in 1950” (p. 155 has a more accurate description). The very interesting information provided on the 1952 arrest of Karl Hamann, a liberal politician and minister of trade and supply German Democratic Republic (GDR), would have gained in significance with more attention to that turbulent time in the GDR and the East-West contest over Germany.

These points aside, there is much we can take away from Allen's work. With all the attention since 1990 on the activities of the Stasi, particularly in the GDR, it is revealing to see how pervasive the activities of other countries’ intelligence services were in West Germany. We have long known that interrogation, informant recruitment, and espionage existed in the FRG, but Allen is correct in arguing it has been understudied, and his book represents a significant addition to our knowledge. Second, the book reveals that the Cold War's “Iron Curtain” across Central Europe was far from sealed. Hundreds of thousands of people crossed it. Although most of them were moving to the West, many also moved (back) to the East, and others went back and forth. All were subjects of interest for the Western services. The larger point is not new either, but again Allen gives us much interesting new detail about the human toll involved. Third, we get an up-close view at times of how the Western services competed with one another for access to migrants whose background and knowledge could yield valuable information on the military or industrial state of affairs in the Soviet Union and the GDR. In particular, we see how West German officials, though often willing to throw in their lot with the services of one or another of the occupying powers, also chafed at the freedom of action these allied services enjoyed in the FRG.

Fourth and finally, Allen suggests that the espionage continued after the end of the Cold War and German unification. Some of the same agencies (German and foreign) have remained active in the gathering of information from new arrivals in the FRG; many of their objectives probably have remained the same (i.e., gaining information on countries and organizations that may wish the West harm); and in the process the FRG's national sovereignty and the individual rights of migrants are in all likelihood nearly as exposed today as they were during the Cold War. The book concludes with an appendix discussing the archival situation in the relevant countries, which will be useful for scholars seeking to build on this important pioneering work. The book tells us a great deal about the interrogation practice of Western intelligence services in Cold War Germany, but as Allen emphasizes, much remains to be discovered and discussed.