First, go to the Overview to see a brief history on the author,Saki Hiwatari!

Before the OAV series, there was the manga. In all there are 21 volumes. You can purchase these at comic stores that carry imported stuff or atleast ask around.

The first Volume looks like this...

The last or "The Final Book," is the most colorful, and is filled with some of the beautiful and original artwork with some reproductions of the previous manga covers.

To find out where to purchase this go here!

Aside from the manga series there is a series of anime books with artwork from the OAV and some new pictures from the PSME Movie.