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.
To become a dragon in the service of Seiryu is to give up our values and beliefs. We must finally seek purity of soul before we can ascend to a mantle of a truly spiritual existence.
We shall no longer pray, for there are none above us worthy of such. We shall become worthy.
We shall no longer idolise, for all idols are false. We shall become ideas.
We shall no longer believe, for that is for the unknowing. We shall become truth.
As the world itself falls away, we shall attain true enlightenment. The spirit dragon shall be born and our essence will fall away into nothingness.
We shall venture into the Well of Spirits, and the charms we have acquired will allow our existence there on the other side for all time.
We shall protect this realm.
We shall protect this world.
We shall protect existence.