Examines intelligence operations in the Pacific War, showing how espionage and codebreaking shaped outcomes. Across the Pacific is a comprehensive history of intelligence in the war between the United States and Japan-how it was gathered, interpreted, and at times fatally ignored. Drawing on decades of research and newly translated Japanese sources, the book examines both American and Japanese intelligence operations across every Pacific theater, including the often-overlooked China-Burma-India front. It explores the rise of Japanese militarism and espionage, the U.S. struggle to understand its adversary, and the decisive intelligence battles that shaped the Pacific War-from Pearl Harbor to Midway, Guadalcanal, and the Philippines, through the submarine and bombing campaigns that brought Japan to defeat. The narrative traces both sides' evolving use of signals intelligence, codebreaking, and counterintelligence, revealing successes, failures, and missed warnings that influenced the course of the conflict. Rich with maps, photos, and original analysis, Across the Pacific illuminates the shadow war of information that underpinned the Pacific's epic struggle.