In Fantasy Westward Journey, writing a letter to a summoned beast required a certain amount of medicine and money, and the success rate of writing a letter was not high. To write a book on a summoned beast, one first needed to choose a high-level writing skill and understand the writing method and success rate of each skill. Then, he needed to choose a certain part of the summoned beast, such as the eyes, ears, or tail, to transfer the skill to that part. The process of writing a letter was very dangerous and required careful operation. Before writing the letter, he had to ensure that the summoned beast did not suffer any other damage and had enough medicine to support it. After writing the letter, he needed to pay close attention to the state of the summoned beast to ensure that there were no abnormalities. It was important to note that the success rate of writing a book was not high and might cause unnecessary damage to the summoned beast. Therefore, it was recommended to carefully consider whether to write a letter to a summoned beast and to understand the risks and benefits before doing so.