What is the purpose and origin of the book 'Sai Leela' as described in Chapter 52 of Sai Satcharitra?

According to Chapter 52, the book "Sai Leela" was created to remember the experiences Sai Baba gave to His devotees while He was in His body. The chapter describes the book as supremely holy, containing stories of His true character that provide enlightenment for this world and the next. It is noted that Sai Baba Himself selected Hemadpant for this task, holding his hand and causing this true life story to be written. The inspiration for the book is said to have come after Sai Baba departed, based on the fame He Himself had narrated to his disciples.