The Negipa Party Book Vol. 13 was released in Japan on August 17, 2007 by Kodansha for ￥476. The book is filled with various information and extras about the manga.
Volume 13 of Negipa mainly focuses on Mana, Ku, and Zazie and is filled with various information about the characters. Also included is an interview with creator, Ken Akamatsu, and the voice behind the featured girls.
In each volume of Negipa, there's interesting tidbits and extras on the series, characters, etc and short fairy tale-esque story focusing on Nodoka inside. In addition, more than half the book features fully colored pages. Also included in each book is a small double-sided poster and a plastic card featuring the character art of the volume's cover.