I like this book. I am basically a beginner in Japanese, and I'm interested in learning to read texts from the start.
The book seems to me a good introduction to short written texts that are managable to do on one's own, with a dictionary.
However, the romanization system this book uses (chi = ti, shi = si, ji = zi, sha = sya, etc - this system, I believe, is called Nippon-shiki) can be pretty frustrating, especially if you speak English (and are used to reading Latin letters based on English phonetics), are used to the Hepburn system, and can already read kana. The author sets forth no compelling explanation for his highly idiosyncratic choice of this non-Hepburn romanization system for use in a book intended for English-speakers. In using this book, I resort to the romanized part only when absolutely necessary. Of course, the best thing would be if the publisher just made a new edition of this book with no romanization or with furigana on the text pages or kana on separate pages after the kanji/kana texts. If you're going to learn Japanese, why not just learn kana from the start? There's absolutely no need for romaji that I can see. It's kind of like learning Russian, Arabic, Hebrew, or Greek, but only learning how to write it using Latin letters. What would the point of that be?
This is a decent book, except for the romanization system used. If you're a beginner and want to go through some managable texts (that gradually increase in difficulty) then this is a good choice, considering that there are few alternative books like this. However, if you are an absolute beginner just note that Mr. O'Neill's romanization system of choice can be confusing because (for the average English speaker) it frequently results in transcriptions that do not "represent" the sounds of the Japanese (e.g., sushi would be "susi", chichi (father) would be "titi", kanji would be "kanzi", etc., under the system Mr. Oneill selected).
Lastly, one nice aspect about this book: It is the size of a regular paperback, so is easy to carry around. For a dictionary, I would recommend Sanseido's "Daily Concise Japanese-English" dictionary (available at Kinokuniya, for example - the current edition is the 6th edition) and a kanji dictionary.