What is considered the most effective form of Guru service through writing, and what does it entail?

According to the preface, the best and most certain service in writing that can grant salvation is to write the biography of one's own Sadguru. This should be done either by the Guru's command or through inner inspiration. As described in Chapter 0, this service is not just about writing; it also involves personally studying the biography regularly, performing hundreds of readings (Parayans) and weekly recitations (Saptahs) with a pure heart, firm faith, and selfless love. This form of service, which engages the body and speech, does not interfere with one's family or worldly responsibilities.