This is quite possibly the best language textbook I've encountered so far. Language textbooks use to have this little problem: they are quite boring. Mr. Smith at the airport; Mr. Smith at a restaurant; Mr. Smith shopping. Not this one: Japanese the Manga Way is fun to read. Who would've thought that language textbooks could be fun?
Its format is quite unique: there aren't long grammatical explanations, and almost all the examples are taken from manga. A lesson begins with some explanation, then a panel from some manga, followed by its translation and notes explaining new or unusual grammatical constructs found in it. Other books use manga panels as examples, so what's new here? Two things: first, the author explains the context in the story for every panel, so that the reader can follow the chain of events and understand what the characters are saying; and second, the book is organized so that examples only rarely use language constructs that weren't explained yet. Furthermore, there are a lot more examples than in similar books, as the whole exposition is guided by them.
This is all very good and dandy, especially if you want to learn to read manga, but it's important to be aware that the book is "an illustrated guide to grammar and structure" as it says on the title, so it's not a complete japanese course. It doesn't present any method to help learning the japanese writing system (kana or kanji), only kana charts at the beginning. Also, it obviously won't help with the spoken language. But within its own objectives, it's a very good book.
A basic japanese course for self-study could be organized like this: first, learn kana & kanji; my recommendations are Heisig's books Remembering the Kana: The Hiragana / The Katakana and Remembering the Kanji: A Complete Course on How Not to Forget the Meaning and Writing of Japanese Characters. Then read this book to get a general feeling for the language; you won't of course be able to memorize all the details given in the notes, but you should get an idea how the language works. You should get a good dictionary too. Then the real learning begins with practice: read lots of manga, watch anime and movies (or TV), listen to japanese music, immerse yourself in the language and culture. And keep Lammers' book nearby; as you read manga you'll encounter many constructs covered in the book, so you can get back there and re-read the notes. With practice, it all gets internalized in your language skills.
And forget about other japanese books that teach through manga: I have the Japanese in Mangaland series, and while it's not that bad, it's not nearly as good as this one. I wish there were more language textbooks like this one, for other languages besides japanese.