Zero, the story of Japan's Air War in the Pacific is an interesting analysis of Japan's air war efforts during the Japanese invasion of China (euphemistically called the Sino-Japanese incident in the book) and the later Pacific War.
The book starts by explaining the Imperial Navy's air arm development during the 1920s, then it moves to the missions flown in China. Of special interest it's the introduction of the Zero fighter to the Chinese air operations and how it boosted the Navy's air-force with its superior performance.
The variety of war theatres this work covers is astonishing, arguably every significant battle of the Pacific War is described here in every possible detail. Initial plans of action, balance of power, data sheets, battle development and the final outcome... everything is analysed by Okumiya. Okumiya himself held several positions as part of the Imperial Japanese Navy staff, and as such, his view of the air operations conducted by Japan are limited to those of the Navy. It would be fair to say that the most relevant missions on the Pacific theatre were carried out by the Navy's air-force, not the Army, but that is definitely a point that prevent this book from giving us the full picture of the Japanese air war on the Pacific.
Also, Jiro Horikoshi contribution to this book is limited to two chapters. One of them dedicated to the many problems the Japanese engineering firms has to face when developing new and existing aircraft, and the second one is an excerpt of a grim diary he kept during the final months of the war. It's a pity that for a book which is entitled after one of the most iconic fighters of WW2, there's not a single word dedicated to its inception.
All in all, this is a great read. It gives us an unusual insight of the Pacific War from the Japanese side, in a honest, detailed and sensible way. For me, the biggest down side is the fact that there's virtually no content about how the Zero fighter came to be.
I also believe this book could be useful for scholars alike, as some of the data sheets are said to come from original classified that Okumiya kept to himself after the war. Don't forget, as I mentioned before, that Okumiya was a member of the Navy's staff so he had privileged access to this information.