If a version is constantly needed, it will be reprinted; If the current purchase volume is less than the actual printing volume, then the publishing house will stock some books and sell them slowly in its own hands. If authors or publishers find that after a period of time (say, five years), the inventory in their hands has been sold out, but the demand for this book is still far higher than the number of prints, they will find that the "version" originally produced during printing may be damaged, lost or neglected due to physical or human factors, and then a new version may be reprinted. On the contrary, if there is no obvious demand in the market, then this book will become extinct.