20th Century Intelligence Operations

Signals intelligence (SIGINT) is an integral part of military strategy. Referring to the interception and decoding of enemy communications, SIGINT is the topic of Peter Matthew's 2013 publication, SIGINT: The Secret History of Signals Intelligence 1914-1945. Matthew focuses on the history of SIGINT until the Cold War. What makes SIGINT: The Secret History of Signals Intelligence unique is that the author presents the Axis point-of-view on SIGINT. As Matthew (2013) puts it, the author's aim is "to tell the other side of the Bletchley Park story," (p. 16).

A brief introduction describes what SIGINT is and how it evolved through technological and strategic changes. SIGINT is related to cryptography, because it encompasses the decoding of encrypted messages. The author points out that the book will be emphasizing Bletchley Park and Ultra, which were instrumental in bringing about the Allied Victory in the Second World War. Moreover, the author is interested in discussing SIGINT from the enemy's perspective: including Enigma and Lorenz (both Germany), Hagelin (Italy) and Purple (Japan). These were enemy coding machines, which Bletchley Park infiltrated.

The author also shows how SIGINT transformed the nature of espionage throughout the First and Second World Wars, in addition to being instrumental in determining the outcomes. Furthermore, the author uses the introduction to show how SIGINT is unique because cryptographers remain unsung heroes often for years after a war is over.

SIGINT the book is divided into eleven chapters, plus the introduction, conclusion, and ancillary material. The first chapter is entitled "From Cables to Codes" and describes the technology of SIGINT from the original cable-based communications, then wireless telegraphy and more sophisticated radio versions. Existing cable-based communications networks had become integral to commerce, and military capitalized on the infrastructure during the war. Although cable technology was more prevalent during the First World War, Matthew points out that cable technology proved to be more vulnerable to interception, and wireless radio started to become a more salient feature of military intelligence. The second chapter, "Intelligent Warfare," discusses more about the interface between intelligence and technology, and shows how politicians leverage military intelligence.

Chapter Three, "The Pre-War Intelligence Scene" sets the scene for the main discussion of the book. Here, Matthew lays the foundation for showing how the Axis and Allies would have an intelligence showdown, outlining the specific projects of each side. This section of the book is relatively brief, but prepares the reader for the meat of the book to follow.

Chapter Four is "Europe's War," and here, Matthew veers slightly off-topic to discuss context and history of World War One. The author mentions oft-forgotten segments of the Austro-Hungarian Empire like Galicia, in the attempt to elucidate Axis perspectives and techniques of SIGINT. Likewise, other corridors of Eastern Europe are addressed in this section. A chapter called "The War at Sea" enhances the primary content of the book by discussing the ramifications of SIGINT in underwater military operations throughout the region. Chapter 6 follows suit with "The War in the Air," while Chapter 7 wraps up the sections on the First World War to show how SIGINT became, at least in hindsight, instrumental for the Allied success. After a surprisingly thorough section on the interwar years in Chapter 8, the author prepares for another central section of the book, on World War Two.

Chapter Nine is entitled "The Second World War: The Beginning," and here the author allows tension to build in the discussion to properly paint a picture of how SIGINT was used on the many different fronts of the war as it grew increasingly complex. Central and Eastern Europe, Northern and Western Europe, the Balkans, the Middle East, and Africa are all addressed in terms of how SIGINT impacted operations in these areas. The middle years of World War Two are addressed in Chapter Ten, in which Russia, Japan, Italy, Sicily, France, Belgium, and Holland used SIGINT including operations spanning the pole. The final chapter of SIGINT wraps up the discussion on World War Two with an explication of SIGINT in D-Day and beyond. SIGINT was clearly integral to the decisions made by military leaders on both sides, and to the strategies that ensued.