A love-letter to Japanese kaiju, or the giant monsters we all know and love, from Godzilla all the way on down to Varan and everything in between. In a slightly-alternate present, Japan has a special government division, the MMD, to deal with giant-monster attacks of all varieties. Like any government agency their work is underfunded, thankless, and tiring; their sole reward for sparing Tokyo from destruction yet again is often nothing more than a hostile round of press coverage and their next paycheck.
The book has a great deal of fun with the mythology of its alternate universe, which gets filled in incrementally over the course of several monster attacks. The first installment pays quasi-homage to "colony"-style monsters like Hedorah—imagine a giant conveyor belt made of lobsters walking itself along the ocean floor—and also serves as a general introduction to the MMD's working habits. We eventually learn that the reason a monster can be sixty feet tall and not fall over under its own weight is because it's, quite simply, not from around here: it's from a parallel universe where the laws of physics don't work the same way.
It's a clever explanation, and it eventually gets woven into a much larger plot involving monsters living among us, trying to stave off nothing short of the arrival of the apocalypse. The book braids together conventional Japanese folklore with the fictional kind, like, oh, the Elder Gods (the Lovecraft fan in me was smiling very broadly at the way this was brought into the story).
In fact, the meta-mythology created by the book is endearing enough that I wanted to see a larger, more ambitious story told about it, one not limited to the confines of a monsterpocalypse storyline. There's also not much in the way of character development or deeper meaning—but since when do you worry about such things when Shinjuku is being stomped flat and Shibuya is in flames? Pick this up along with Criterion's recent reissue of Godzillato see how they both occupy extreme opposite ends of the same continuum.