What book is this in calligraphy?

This is a typical Li Si seal script, called Jade Seal Script, also called "Jade Seal Script". As the name implies, the font strokes are thick, just like jade seal lines. Chen Qing Feng's "Imitation Seal" said: "The strokes of seal script are even at both ends, and those that can't stand out at the end are called' jade chopsticks', and seal script is an original." Ming Ganyu's "Seal Collection" said: "Jade chopsticks, that is, the biography of Li Xiaosi." The representative calligraphers of jade seal script are Li Si in Qin Dynasty and Li in Tang Dynasty. At the same time, this is Xiao Zhuan. You can download it from Baidu. There are many references.