Origins of the Book: Spies for Nimitz began as a master's thesis on the role JICPOA played in the Iwo Jima campaign. Naval History and the Army's Military Intelligence Professional Bulletin subsequently secured two of Moore's articles on the subject, and from then on the project grew to cover all of the major Pacific amphibious campaigns carried out under Admiral Chester Nimitz.

Modular Organization:  Each chapter in Spies for Nimitz is modular, so readers can easily find sections of interest or utility.  A typical chapter includes sections on a battle's historical background, why the U.S. military targeted a particular island, the intelligence operations against an island, how intelligence impacted a battle, and conclusions.  Readers with a special interest in any one campaign or specific intelligence issues will appreciate Moore's precise organization of the book.

Why Spies for Nimitz?: The historical record of the Pacific War yields few report cards related specifically to how intelligence impacted the most pivotal island battles. Moore's unique contribution in this highly readable book is a rigorous analysis of outcomes, island by island, showing whether intelligence had or had not accurately assessed Japanese capabilities and intentions.

Subject: Spies for Nimitz discusses the history and operational procedures of America's first modern military intelligence agency: the Joint Intelligence Center, Pacific Ocean Areas, or JICPOA, and how its intelligence operations affected eight island assaults executed under Admiral C. Nimitz, Commander in Chief of U.S. Pacific Forces in World War II. The book also provides scores of real world lessons learned, derived from hard-fought amphibious campaigns.  Many of those lessons came directly from the intelligence officers who constructed, operated, and commanded JICPOA, and they are applicable to problems faced by the present-day intelligence community.

Background: JICPOA was one of several key predecessors of America's modern intelligence agencies, and many of its personnel went on to help create the Central Intelligence Agency, the National Security Agency, and the Defense Intelligence Agency.

At full capacity, JICPOA had 1,767 intelligence professionals processing all-source intelligence information from photographs, radio signals, captured documents, and prisoners of war for naval, marine amphibious, and air operations. JICPOA's sources were basically the same as those used by its present-day counterparts. When it could, JICPOA interviewed people who had lived on a targeted island and had intimate knowledge of its terrain, infrastructure, and hydrographic features.

Short History: When the Japanese attacked Pearl Harbor, the U.S. Pacific intelligence community consisted of several small groups. They were too fragmented to be really effective in gathering and disseminating intelligence, and none of them was large enough to support amphibious island campaigns, which were considered necessary to carry the war to Tokyo. Even as Pearl smoldered, Lt. General Thomas E. Holcomb, Commandant, USMC, was proposing that a joint Army, Navy, and Marine intelligence center be established to support large island assaults and affiliated naval operations in the Pacific.

and years following December 1941, Admiral Nimitz added more sections as needed. Eventually, this formed an interim intelligence unit called ICPOA, short for Intelligence Center, Pacific Ocean Areas. It was mostly a naval intelligence unit, but it continued to grow by taking on new intelligence functions and by absorbing smaller, disparate military intelligence units that belonged to the military services. By 1943, the organization resembled the one proposed by General Holcomb. Accordingly, Nimitz officially christened it JICPOA in September 1943, just in time for it to support the island hopping campaign that would take the war to Tokyo's doorstep.

Structure: JICPOA consisted of four groups, each with a particular area of expertise. Every group contained sections or "desks" that focused on a specialized subject. For example, Group One focused on static information, such as Japanese military bases, industries, terrain, health, etc. Group Two concentrated on analyzing the various branches of the Japanese military. Group Three contained psychological warfare, and escape and evasion sections. And Group Four concerned itself with administrative issues, security, and most importantly, dissemination, a sometimes neglected but pivotal phase of the intelligence cycle.

Sources

Sources: The primary sources for Spies for Nimitz include JICPOA's historical records, official documents at the Marine Historical Center and the research lab at Quantico, and interviews with a number of JICPOA veterans. One of them, Rear Adm. Donald M. "Mac" Showers, was the first U.S. Navy officer permanently assigned to JICPOA.

Primary sources offering conclusions and assessments of the various operations failures and successes, such as Marine and Navy after-action reports, were thoroughly helpful but rare.  Likewise, secondary sources containing the same, such as Jeter Isely and Philip Crowl's venerable The U.S. Marines and Amphibious War, and newer classics such as Joseph Alexander's concise Storm Landings, were pivotal in deciphering how intelligence impacted these operations, but also few and far between.

The conclusions drawn in Spies for Nimitz are largely Moore's own, drawn from link analyses and comparison and contrast methodologies by putting intelligence reports, operation planning information, battle accounts, and post battle analyses side by side. For each operation, the book provides a documented surmise about how intelligence affected the outcome.

The author's analysis of the Pacific campaigns took about five years to complete. The book includes a complete bibliography of primary and secondary sources.

Before and After: Examples of Analyses

Kwajalein Atoll: Official records showed that the naval preliminary bombardment for Roi-Namur, a small island airbase within Kwajalein Atoll, had destroyed most Japanese beach defenses and strongpoints. A review of JICPOA's Roi—Namur intelligence bulletin demonstrated that the Americans knew volumes about Japanese defenses there. Intelligence maps showed specific gun positions, such as blockhouses, pillboxes, antiaircraft sites, and infantry trench lines. Accordingly, this indicated that JICPOA's intelligence contributed to an accurate and devastating bombardment, and deeper research of post-battle documents confirmed this analysis.

Peleliu: U.S. Marines attacked Peleliu in September 1944. The Marine record of the bloody assault documented scores of specific pillboxes, blockhouses, and earthen defenses between the beaches and the islands airbase, the Marines' ultimate objective. JICPOA's prebattle intelligence for Peleliu, which included text and detailed maps, indicated none of these fighting positions, nor did it assess the extent of the island's incredibly rocky terrain, which served as a force multiplier for the defenders. Several citations in the Marine record pointed to significant intelligence deficiencies that described how shocked the Marines were at Japanese defenses for which they were not prepared despite the impressive array of intelligence documents they had going in.

Iwo Jima: An abundance of all-source intelligence was available to operational planners before the landing on Iwo Jima. According to Marine records, photographic reconnaissance of the island was some of the best of the war, and captured documents were expected to be helpful here, too. Yet the battle cost over 6,000 killed in action and about 23,000 wounded. It was by far the toughest fight in the Pacific up to that point, and perhaps the most difficult of the entire war.

JICPOA's intelligence for Iwo Jima was detailed and well prepared. It said with certainty what weapons the Japanese had, how many men they had, and how they planned to defend the island. But intelligence only provided half the picture.  Many more Japanese occupied the island than JICPOA originally figured.  Neither did JICPOA provide any warning of the island's incredibly difficult terrain, the Japanese use of caves, and their heavy reliance on concrete and steel fortifications.

Discovering why JICPOA got it wrong required deep analysis. Marine after-action reports and the official record of the campaigns helped reveal the truth. Even JICPOA's own historical log exposed a major functional defect in the U.S. Navy's administration of the intelligence community that contributed to intelligence failures such as that at Iwo Jima.