The preface to
Japanese in Mangaland has a very good discussion on the phenomenon of manga.
[introducation and the first of two reasons why this book uses manga]
The second reason is that manga is a real phenomenon, not only in Japan, its country of origin, but also in the rest of the world, where it has gradually been spreading and becoming increasingly popular and accessable.
The word "manga" literally means "spontaneous and meaningless drawings", and is used in Japan when referring to comic books. By extension, the West has adopted this word with the meaning of "Japanese comic book." However, the popularity of manga in Japan cannot be compared with anything similar in Western countries. There, the manga phenomenon could just as easily find its equivalent in films or some popular sport. A manga author can charge a remarkable amount of money per page drawn. Here are a few illustrative data:
a) In 2001, 38.2% of all books and magazines published in Japan were manga, producing 22.9% of total benifits of the publishing industry of Japan, according to the 2002 Shuppan Shihyo Nenpo (annual publishing index)
b) Weekly manga magazines have amazing print-runs. It is not rare in the Japansese market to have weekly manga magazines selling over a million copies every week. For instance, in 2001, Shonen Magazine and Shonen Jump sold an average of 3.5 million copies weekly... Nothing compared to the 6.5 million weekly attained by Shonen Jump in its golden age of the end of the 80s and the beginning of the 90s.
c) The industry manga has given rise to cannot be ignored: cartoons or anime, now a great success throughout the world, are a clear example.
There are manga of all kind of interests, plots, artistic styles, and for all ages and social strata. There are manga for young people, teenagers, housewives, laborers, office workers, even erotic and pornographic manga, and so on. In Japan, manga is not only for children... In fact, everybody in Japan reads or has read manga, and thier culture is obviously influenced by it.
Manga is not only science fiction, violence and blood shedding, in fact there is ALL kind of manga, but those that reach the West are mostly the violent type, which has contributed to create a distorted view of what manga really is. Personally, I recommend reading Osuma Tezuka's works, for instance, to understand manga can be an authentic art.
From my point of view, the idea that "all manga are the same," speaking in terms of graphics is another mistake. In the West, when we talk about manga, the image we immediately have is that of slender people with huge and shiny eyes. Many manga certainly have that kind of aesthetic, but all you need to do is take a look at authros like Naoki Urasawa, with his realistic style, or at a series like Crayon Shin-chan, in which charachters appear completely deformed. And there are countless other examples.
manga are originally published in thick, cheap weekly magazines, at around 20 pages per week; Shonen Magazine, Shonen Jump, Big Comics, Shonen Sunday, and a long list of other magazines are among the most well known. When a series is successful, it's usually compiled into a volume of about 200 pages (compiled of about 10 or 11 chapters previously published in a weekly magazine) called tankobon, which is how it usually reaches Western readers who get hold of manga in Japanese.
All in all, manga is a very important phenomenon in Japan... [more stuff about the book]
edit--- alicia feels that I did not clearly credit and state that the above is from the introduction to the book. i.e. i did not write it. It was written by that author, Marc Bernabe