China has published its first encyclopedia of its 56 ethnic groups.

The 15-volume encyclopedia has more than 45,000 entries and 6,400 color images. It deals mainly with the history, politics, military, religions and customs of the ethnic groups.

The Han ethnic group makes up around 91 percent of the total population, according to the 2010 census.

Some 1,000 researchers have been involved in compiling the encyclopedia since 1997, according to the editor-in-chief Li Dezhu.

Late ethnologist Fei Xiaotong, also honorary editor-in-chief, said in the foreword that the book will open a window for the world to understand China's ethnic groups.

Fei passed away in 2005.