When I saw that a good looking new English bento book was released, and from a Japanese author, I had to have it right away. This is only the second English bento book I have. If you are interested in bento making and can't read Japanese, I say get this book RIGHT NOW. You should have no hesitations whatsoever.
If you can read Japanese, you probably wouldn't be looking at this book anyway, but just in case: I highly advise you to skip on this book because there is nothing new in it that you won't find from much better books. A few recommendations are つくりおきおかずで朝つめるだけ！and おべんとうつくりの正解.
That being said, let's get to the actual review of it as a cookbook:
I found the recipes authentic yet very simple. There are decidedly Japanese bentos (ex. Rolled omelet and boiled hijiki bento) and very non-Japanese bentos (ex. French toast salad bento) included in the book to satisfy every palate. However, quite a few of the recipes include Japanese items that may not be easily found in your regular grocery store. I believe this is because the book is just a translation from its Japanese counterpart. Things like seven-spice powder, yukari, konjac, wakame, hijiki; I definitely do not have in any grocery stores near me. I would not even know what some of these items were if it wasn't for my Japanese bento books. But at least half of the recipes use only common ingredients (assuming you have access to things like mirin, sake, rice vinegar, miso). If you have an Asian store near you, no problem. I personally make bentos every day of the workweek and prefer to use ingredients I can obtain easily.
One thing that should be noted is that this book is based on bentos that have the sides on top of the rice. That is the case for every bento in the book that has rice, and the ingredients and toppings are selected to be appropriate for that purpose.
Compared to my other bento books I found this book rather thin, empty, and void of content in general. I read the entire book in less than half an hour. (Yes I did read an entire cookbook, to get an idea of all of the recipes) I do like the presentation and organization of the book, though. Most probably it looks so empty because all of the recipes are as concise as they can possibly be, but the book just left me wishing there was more in it. For example, in the Just Bento Cookbook, most recipes come with variations and in depth explanations of what works, what doesn't work, and why. But it still did have some nice ideas I hadn't thought of before, such as the easy ham katsu, and quail egg topping.
If you are an absolute beginner in bento-making, I don't think you can jump in and begin making these recipes right away. The explanation of recipes are very short. Even for simple things like tamagoyaki or teriyaki, I think one needs a thorough introduction when they first begin making them. So for a beginner, I would recommend The Just Bento Cookbook as a first step, and this book as a second step.