How does the book compare the concept of a Sadguru with the role of prophets or spiritual guides in other world religions?

The preface of the Shri Sai Satcharita does not draw direct comparisons between a Sadguru and figures from other world religions. The text's scope is focused on the principle of the Sadguru as understood within the tradition of Aryavarta. Chapter 0 establishes that this principle is very ancient, dating back to Vedic times, and holds that salvation is not possible without the grace of a Sadguru. It does, however, highlight the universal accessibility of this grace, stating that a Sadguru may belong to any caste or religion and can manifest in various forms, including as a book, parent, or friend, not just a person.