Describe what the author considers the ultimate and most certain form of written Guru service for attaining salvation.

Based on the preface in Chapter 0, the author's humble understanding is that the best and most certain written service for achieving salvation involves several key elements. It begins with writing the biography of one's own Sadguru, prompted either by the Guru's command or by inner inspiration. This act of writing must be followed by personal, regular study of the biography. This study should include performing hundreds of readings (Parayans) and weekly recitations (Saptahs) with a firm resolve, pure heart, excellent faith, selfless love, and unwavering devotion. Finally, one should also encourage other devotees to do the same.