The preface states a Sadguru can be a book or a family member, yet also quotes Dnyaneshwar Maharaj on serving saints. How are these ideas connected?

The preface, as presented in Chapter 0, establishes a broad and inclusive definition of a Sadguru, which can be a person, a book, a deity, or even a family member. It then cites Dnyaneshwar Maharaj's teachings from the Shri Dnyaneshwari, which emphasize serving saints with one's entire being—body, mind, and soul—without ego. While the text doesn't explicitly link these two points, one can infer that the core principles of service described by Dnyaneshwar Maharaj are the method by which one should approach their chosen Sadguru, regardless of the form that Sadguru takes. The emphasis is on the devotee's complete surrender and selfless devotion.