If lost or destroyed, a new copy can be obtained from the bookcase in your Player-Owned House made through Construction.
Below is the text you can read from within the book.
Seiryu is one of the four guardians on Wushanko, but being a spirit of water makes it the purest of the four. Our own bodies are impure, as are our thoughts and actions.
To become a monk in service of Seiryu is to give up our earthly, physical pleasures. We must first seek purity of body before we can ascend to the next mantle of existence.
We shall eat and drink only from natural sources, and only enough to sate our hunger. Much fasting is required.
We shall not exert ourselves physically for competition. Hours alone in meditation shall be our sport.
We shall lie alone in our beds, and put aside carnal thoughts. Many visits to the Urn of Cleanliness will be required.
We shall not partake in violence, save to defend ourselves and our brothers and sisters. Our deaths shall buy us enlightenment.
As our old lives fall away, we shall attain the charms of the azure dragon, which are necessary for us to enter the next realm. The water within us shall become without and our bodies shall fall away into nothingness.