The author Balkrishna Vishwanath Dev wrote the preface. Who does he name as his personal Sadguru in this section?

In the provided text from the preface, the author, Late Balkrishna Vishwanath Dev, does not explicitly identify his personal Sadguru. Chapter 0 begins with a salutation, 'Salutations to Shri Datta-Chit-Sai-Guru,' but the text does not elaborate on this or definitively state that this is the author's own Guru. The preface proceeds to discuss the general importance of writing the biography of one's Sadguru, whether by command or inspiration, but it refrains from providing personal details about the author's own spiritual master.