Chapter 45 mentions that Sai Baba's physical form vanished but his 'literary form' remains. What is this literary form and what is its purpose?

According to Chapter 45, while Sai Baba's physical incarnation came to an end, his presence continues through his 'literary form,' which is the Shri Sai Satcharitra itself. The purpose of this book, as detailed in the chapter, is to provide remembrance of Sai at every step. Listening to these stories is described as a 'supremely holy act' that allows the mind to attain a unique and indescribable peace through concentration, ensuring that Sai's essence and guidance remain accessible to his followers.