What personal experiences did the author, Balkrishna Vishwanath Dev, have with his Sadguru that led him to write this preface?

The preface by Balkrishna Vishwanath Dev does not contain details about his personal experiences or his specific relationship with his Sadguru. Instead, the text serves as a philosophical introduction to the importance of Guru service. In Chapter 0, the author presents what he calls his 'humble understanding' of the topic. He argues that the highest and most certain form of service for attaining salvation is to write the biography of one's Sadguru, either by command or by inner inspiration, and to study it with unwavering devotion. This is presented as a principle rather than a personal narrative.