Voume Infinity is a doujinishi artbook published by Naoko Takeuchi herself. It was distributed by Naoko at Japan's Comiket 1997. Very few of these artbooks exist, (...) The book contains artwork drawn by Naoko Takeuchi, as well as artwork by animators, seiyuu, and staff members who worked on Sailor Moon.

From http://soul-hunter.com/sailormoon/galleryartbooks/infinity/index1notes.php