Shuowen Jiezi
Shuowen Jiezi (說文解字) was the first Chinese character dictionary, compiled by Xu Shen between 100 CE and 121 CE in Han Dynasty China.The work explains the character origins, and various more recent versions of it are known of, but the original version is lost. The most famous are those from the Song Dynasty, but there are a number from the Qing Dynasty like 說文解字注 compiled by Duan Yucai.
See also: Seal script