This book is a collection of selected newspaper column installments for English-speaking foreigners learning the Japanese language.
The writing style is memorable, witty, and engaging. It gets the point across, and I can see why the newspaper columns must have been popular.
At first, however, it is a little confusing until you realize that the intro to each chapter is written from the context of two people in Japan, using humor, talking about the language, and that "Pole-san" is the bumbling learner of Japanese asking a direct question because he is confused.
The only reason I did not give the book a 4 or 5 is because some of the information is titillating, but of limited or questionable usefulness (and even then mostly in casual conversation in Japan, as opposed to in the office). Probably the best example of this is the chapter, "Doing Sumo in Someone Else's Underwear" -- a chapter explaining some very strange Japanese sayings. At some point this information just *might* be useful for a person hearing someone say these things.
On the other hand, the explanation of "wa" vs. "ga" adds a more information to that gleaned from textbooks. The examples of how Japanese use phrases to remember phone numbers by including phonetic syllables that make up the numbers within a sentence (very different from the way we use 1 or 2 words and map them to letters on the dial pad) is a revelation and is totally ignored by any text I have come across.
The usefulness of the information in each chapter varies, and so does the content (or lack thereof) within each. Some chapters contain almost no information at all, others actually explain important conversational quirks and grammatical stumbling blocks as well or better than textbooks, and in a clearer and more memorable way.
If you think this book will be like a "guide" to "Better Conversation", you'll be disappointed, but if you want to be entertained, fit a few important lessons there, and need "one more book" to cover some points missed elsewhere, this book can refine your skills a little bit and maybe prevent you from a few select mistakes.
Maybe if you have traveled or will be traveling to Japan, this book will provide one or two "AHA!" moments that make it worth the purchase. But don't look at this as anything like "the one book you need to have" to refine your conversation, it is too lite on content for that.