Cai Kui shu 蔡葵書 "Book of Cai Kui" was a book on agriculture compiled during the Former Han period 前漢 (206 BCE-8 CE) by Cai Kui 蔡癸, who lived during the reign of Emperor Xuan 漢宣帝 (r. 74-49 BCE).
In Liu Xiang's 劉向 (79-8 or 77-6 BCE) bibliographic treatise Bielu 別錄 it is said that Cai Kui hailed from Handan 邯鄲 (modern Handan, Hebei). About his life is not much known except the fact that he was a "high official" (daguan 大官), probably governor (taishou 太守) of the commandery of Hongnong 弘農, and was very interested in promoting agriculture.
His book was just one-chapter-long, as can be seen in the imperial bibliography Yiwen zhi 藝文志 in the official dynastic history Hanshu 漢書. In Cui Shi's 崔寔 (d. c. 170 CE) book Zhenglun 政論 it is said that Cai Kui instructed the people in the methods of field cultivation, probably Zhao Guo's 趙過 method of crop rotation (daitianfa 代田法).
A few surviving fragments of the Cai Kui shu were collected by the Qing-period 清 (1644-1911) scholar Ma Guohan 馬國翰 (1794-1857). They are to be found in his series Yuhanshanfang jiyi shu 玉函山房輯佚書.