I've always had an interest in the IJN, and I was really looking forward to reading this book when it came out. Unfortunately, it's not a whole lot more than a rehearsal in new formatting of the information you could have gotten fifty years ago from AJ Watts' Japanese Warships of World War II. The book has a short introduction and conclusion about the operations of the IJN in the war, and these parts bizarrely show no knowledge of the American deciphering of the Japanese naval codes and the affect of this on operations. The main body is discussion of the various classes of the warships of the IJN grouped by chapter according to category of ship (carriers, battleships, cruisers etc.) and arranged in chronological order. There's an introduction for each chapter that gives a pretty cursory description of the development and employment of the category of ships, and then each class has a discussion of a) design and construction, b) armament, c) service modifications, d) wartime service. The armament stuff gets pretty boring, and while the employment of capital ships can be meaningful, the piling up of disconnected campaigns of destroyers and especially submarines borders on the useless. In particular, the circumstances of the loss of the lesser ships is often so succinct as to be meaningless. Instead of the endless litany of mind-numbing facts, a bit of comparative discussion of how the Japanese ships stacked up to the corresponding ships of other countries would be more informative.
There are some nice schematic color drawings with cutaways. Unlike the Watts book, some of the technical information is presented in separate tables, which can make consultation easy. There are lists of translations for the names of ships down to cruisers, but for no readily apparent reason there is no listing of the often rather poetical sounding names of destroyers. A particular fault of the book are the inferior illustrations. It seems as if these come mainly from two sources, and while some are clear, a disturbingly large number are very fuzzy. I know from personal experience what a pain in the ass it is these days to get images with a proper copyright lineage to allow for publication, but I think that much better images could have been gotten, and if you're going to have a book full of illustrations, it would be a good idea to make sure to get the best ones available.
Not sure that the book really is much of an improvement over Watts', which was also more all-encompassing, including classes like destroyer escorts that are ignored here. Also, I may be old-fashioned, but I find it jarring to hear major vessels referred to as "it". I had to do a whole lot of mental conversion to "she", "her" etc!