The Sri Sai Satcharita, Baba's miracle text and panacea for all problems, was written by a devotee of his named Hemadpant. But, did Hemadpant actually come up with the words? Read what Baba said about this in the Sri Sai Satcharita:
"I (Hemadpant) could not myself ask Sai Baba to give me permission for this work; so I requested Mr. Madhavrao Deshpande alias Shama, Baba’s most intimate devotee, to speak to Him for me. He pleaded for my cause and said to Sai Baba:
"This Annasaheb (Hemadpant) wishes to write Your biography, don’t say that You are a poor begging Fakir, and there is no necessity to write it, but if You agree and help him, he will write or rather, Your feet (grace) will accomplish the work. Without Your consent and blessing, nothing can be done successfully."
When Sai Baba heard this request, He was moved and blessed me by giving me His Udi (sacred ashes) and placing His boon-bestowing hand on my head said:
"Let him make a collection of stories and experiences, keep notes and memos; I will help him. He is only an outward instrument. I should write Myself My autobiography and satisfy the wishes of My devotees. He should get rid of his ego, place (or surrender) it at My feet. He who acts like this in life, him I help the most. What of My life-stories? I serve him in his house in all possible ways. When his ego is completely annihilated and there is left no trace of it, I Myself shall enter into him and shall Myself write My own life. Hearing my stories and teachings will create faith in devotees’ hearts and they will easily get self-realization and bliss."
~ Sri Sai Satcharita, Chapter 2
So as you can see, Baba himself wrote the Sri Sai Satcharita, Hemadpant was only a medium. Even the commentary, which appears to come from the author, in fact comes directly from Baba. Keeping this in mind, it adds a whole other dimension to this great work.