The reviews for this book here on Amazon are divided, and you can understand both responses, respect and rage.
This volume is what it claims to be: an account of colonization, Japan of Korea from the late 1890s to the early 1920s (but ending before the more brutal culling of the Imperial War Machine in the 30s and 40s).
The first half collects the various arguments made in Japan from the 1860s onward: cultural, racial superiority, expansion and capitalism, contending and competing with the West, in the creation of justifying colonization. Particularly useful if the reader has the basics on the ideology of colonialization, Albert Memmi, Franz Fanon, Edward Said etc. Or the other way around: for the reader who is reading up on colonial writings would find the non-Western discourse on colonialization interesting, the discourse on racial destiny and the Japanese "burden" to enlighten Asia, compared to the "White Man's burden."
The second half of this book catalogues, with official figures and many personal accounts of Japanese life in Korea, for the middle-class and aspiring middle-class entrepreneurs who sought to take advantage of the colonial government and the expansionist policies of the time. And it is particularly useful as a (scholarly) portrait of people, history written from the bottom up, instead of mainly from governments policy and war.
The book is written by a Japan scholar, from Japanese documents, so the reader must take into account the sources (and sympathies) involved, the author's lack of current Korean, Korean sources and scholarship, and the text's (near) absence of Korean agency alongside the efforts at Japanese economic absorption. It offers only a hint (in the occasional phrase) at the tolls of economic policies on "normal" Korean people as people (human beings with lives and names), in its report of the lives of "normal" Japanese. But perhaps that is not this volume's purpose.
For a volume written 10 years ago, it's a valuable and readable resource, more useful when read with the collected essays in "Colonial Modernity in Korea" that was published around the same time (Eds. Gi-wook Shin and Michael Robinson, 1998) for a fleshed out view of life in the late 19th century and early 20th.
Hopefully, almost 10 years after this volume, and with the emerging generation of East Asian scholars, trained in Korean, Japanese, and Chinese, we'll find fuller, more nuanced and complex accounts of history.