The Book of Zhou (Zhōu Shū) records the official history of the Xianbei-led Western Wei and Northern Zhou dynasties of China, and ranks among the official Twenty-Four Histories of imperial China. Compiled by the Tang dynasty historian Linghu Defen, the work was completed in 636 CE and consists of 50 chapters, some of which have been lost and replaced from other sources.The book was criticised by Liu Zhiji for its attempt to glorify the ancestors of Tang dynasty officials of the time. Source: Wikipedia (en)