This book covering the whole of Japanese history from prehistory to the present day is, in its paper & ink version, just 236 pages long, including a glossary of 50 Japanese names and terms, a brief bibliography and an index. Don't expect it, then, to explain anything with much detail or depth of analysis: you can't possibly do justice to six thousand years of Japanese culture and history in 200 pages of rather large-ish print. It's a serviceable, perfectly good little summary, like a collection of well-written encyclopedia entries on the basic periods of Japan's history.
If you just want that kind of brief introduction, perhaps to read in one sitting on the plane on your first trip to Tokyo (even if you travel from Seoul) so you will get the basic facts & characters and not get lost in translation when visiting Osaka Castle or the Imperial Palace; or maybe to learn some essential context before watching some samurai movie classics or reading historical manga, then this may very well be the book for you. But if you are a history buff that wants something with more substance, that explains and analyzes the damn facts at length, then look elsewhere. This will be a frustrating read. For me it was like getting a taste of every dish at a fantastic restaurant, without being able to actually eat any of them.