This follows the same clear and varied format as Books 1 and 2, but of course this time gradually introduces a few Kanji. This is done in a straightforward no-nonsense way.
Subject matter is again relevant and interesting.
Where the book is let down is the suddent introduction of words or uesage of words that have not yet appeared in the text. One phrase, for example, is casually thrown in some 8 chapters too early. In addition there are spelling mistakes in both English and more critically (considering the nature of the book) in Japanese too.
So a good product marred by some very clumsy editing, but still with the same effective style of presentation shared by the earlier books in the series.
Another minor criticism is some of the choice of vocabulary. I find it odd that "North Pole" and "Equator" were needed at this stage! However, it could be argue they were just contextual to the stories being presented.
It also makes use of the informal style in places that, in fairness, wasn't really covered so well in Book 2. This may require a serious revisit by readers.
I am giving it 4 stars but it only just scrapes the 4th one.
Incidentally I can recommend their website, although it's pay-by-month. If you can afford to pay for just a single month you will get valuable exposure to native Japanese speakers. I found that a very good resource to accompany this series.
Books 4 and 5 appear to be on hold, but do appear in electronic form on the site.