What is manga? (ma-n-ga)
Manga can be roughly translated as "comic books", in reality it is a much more complex subject. Manga can include almost every subject imaginable from funny stories to serious literature.
Technical manuals and even legal case histories have been released in manga format. Looking at some books about manga, especially those of Frederik Schodt, will probably be the best way to understand this unique form of publishing.
Many companies outside of Japan are issuing translated manga in multi-volume sets at an increasing pace. In most cases they are no longer flipping the images and leaving the manga in the original right to left format. There are two reasons to do this, some manga artists will not allow their art to be flipped to a European left to right format, the other reason is that leaving the art unflipped reduces the time and expense it takes to bring a translated title to the market by eliminating much of the retouching of images. I have discovered that most readers have little trouble reading unflipped manga, something that caught me by surprise.
Note: What librarians should know is that manga are usually published as serialized stories in magazines which are later often collected into book form. The result of this can be a series of volumes for one long story, as is the case with some of the comedy and supernatural series of the talented Takahashi Rumiko, the adult political thriller Sanctuary by Fumimura and Ikegami or the equally adult Lupin III series by the unusually named Monkey Punch.