In Combined Fleet Decoded, author John Prados presents us with a history of the gathering and use of intelligence by both sides in the Pacific war. The time period covered is the two decades preceding the war, on through to the cessation of hostilities in 1945. All participants are examined on the Allied side, not just the U.S., but also the Dutch, British and Australians. Whereas most historical accounts highlight radio intelligence and cryptanalysis, Prados runs the gamut of other types of intelligence as well: naval attachés, air and photo reconnaissance, salvage of critical documents from sunken or captured enemy vessels, prisoner interrogation and coast watchers are all covered. Prados benefits immeasurably from having written this book when he did, in the 1990s, after the declassification of many Pacific war intelligence documents that occurred around 1980 or so. My attention was first drawn to Combined Fleet Decoded because so many recent works cite it as a secondary source, such as Parshall and Tully's Shattered Sword, Lundstrom's Black Shoe Carrier Admiral, Hornfischer's Last Stand of the Tin Can Sailors, and undoubtedly many more that I have yet to encounter.

Prados is explicit as to where he believes intelligence stands regarding U. S. success in so thoroughly defeating Japan. He states that starting with Coral Sea and Midway, on through the conquest of the Solomon Islands, it was intelligence that provided the edge for the U.S. to prevail, since materially the two antagonists were roughly even. Once the second generation American fleet carriers and fighter planes began to arrive in the Pacific, and Nimitz's central Pacific drive started with the Gilberts and Marshalls invasions, the Japanese fell behind rapidly in resources, with the gap only widening through the remainder of the war. It is in this second phase that Allied intelligence was no longer the predominant factor for U.S. success. From then on, it was the far superior industrial output of the U.S. that provided the ever increasing margin of victory, but with intelligence still a very important force multiplier.

Combined Fleet Decoded is a complete history of the Pacific war, viewed from the perspective of intelligence. If the book were arranged thematically, without respect to the narrative of the Pacific war, it would still be of great value due to its thoroughness. However, the author does provide a narrative, and the topics regarding intelligence are presented and discussed at the point that they appear in the story. Therefore, we get a compelling story, the pace of which is kept up by intelligence developments along the way. Although a complete history of the Pacific war, Combined Fleet Decoded is not an ideal introduction to the topic. As another reviewer has mentioned, it would be helpful to the Pacific war neophyte to first read Samuel Morison's nine volumes on the Pacific theater to get a grasp on the geography, personalities and chronology of operations, so that Combined Fleet Decoded could be better understood and appreciated.

Very highly recommended - an absolute must-read for serious students of the war in the Pacific.

Prados thoroughly addresses intelligence gathering and analysis on both the U.S. and Japanese sides. However, what stands out most is the depth of information on the Japanese experience. Can't think of another title that provides nearly as much insight into Japanese thinking as the war in the Pacific progressed. His discussions of Decisive Battle are nuanced and enlightening.

Moreover, meticulous timeline reconstruction based on intercepts and decrypts, traffic and signals analysis, etc. allows Prados to dispel many of the widely-held inaccuracies and outright myths around many of the strategy decisions and battles in the Pacific during WW2 and puts this in the same class as Parshall/Tully's Shattered Sword (Midway).

The author did a good job at presenting how each side treated intelligence. If it lacked anything I would say it was in presented limited reasons why the Japanese tended to ignore or pay lip-service to intelligence. Was it part of their culture? The author did a good job describing where the Japanese went forward with plans in spite of limited understanding of the enemy potential. While the author could have done better in that area I thought he did a good job of contrasting the differences between the Japanese and Americans in this area.

John Padros has a very relaxed and easy to follow writing style. He's able to add details without overwhelming the reader. One decision I like is that he presents and discusses the differing viewpoints or conflicting information regarding issues and then leaves it to the reader to decide what seems the most feasible.

Like reading the backgrounds of the different Americian and Japanese personalities involved in the Pacific War. Not alot of overwhelming details but enough that each person when mentioned becomes a distinct character.

Very enjoyable and informative read; highly recommended for those interested in greater detail about events of the Pacific War.

The definitive book on decoding the Japanese Navy's secret messages. Thoroughly researched and well documents.

It filled in a lot of info on WW2 that I hadn't known. As a former navy crypto officer, I had hoped for more details on how the Japanese code was broken.

This book tells the Pacific War from the point of view of both sides' intelligence forces, focusing on SIGINT and COMINT analysis. If that sounds dry, the story is fascinating and riveting. Essential reading for anyone interested in the Pacific War or the consumption of military intelligence.

Extremely informative book on how the United States navy was able to defeat a vey good Japanee navy