According to Chapter 52, how did the 'Sai Leela' book come into existence and what is its stated purpose?

Chapter 52 explains that Sai Baba Himself was the driving force behind the creation of the book, which is also called "Sai Leela". He chose Hemadpant for this task, holding his hand and causing the true life story to be written, despite Hemadpant's own feeling of being devoid of specialized knowledge. The chapter mentions that some of the fame was narrated by Sai with His own mouth, and the inspiration for the book came after He departed. Its primary purpose, as described in the text, is to remember the experiences He gave to His devotees and to provide enlightenment for this world and the next.