This torrent contains three volumes (1-3) of "The Japanese the Japanese Don't Know", a series of short comics and essays regarding the finer points of Japanese grammar and usage.  

"Absolutely hilarious and educational book. Best seller in Japan. "The Japanese the Japanese Don't Know" is a collection of stories about a teacher of Japanese in Japan and her students, what sort of questions they ask, what sort of mistakes they make, etc. There's also a lot of interesting background on the Japanese language, like where certain words came from and such. For example, masu/desu is now standard Japanese, but it used to be geisha-speak. Men came to the capital, heard geisha speaking that way, and took it home and spread it, thinking it was the way everyone in the capital spoke. There was also a lot about keigo (formal speaking), and how even Japanese people get it wrong a lot. Highly recommended for intermediate/advanced Japanese students. All kanji with furigana reading." - Amazon

This torrent does not contain Volume 4, which I've been unable to find.  As usual, if you find it or have it, share it!  :)