How can devotees serve their Sadguru and build a community through literature, as described in the preface?

The preface explains that a Sadguru accepts two primary forms of service from devotees through books. As detailed in Chapter 0, one way is when the Sadguru creates great works themselves, like the Shri Dnyaneshwari. The second, more common method is when the Sadguru has their biographies written by devotees. The community then engages in service by studying these works and performing Parayans or Saptahs. This act of collective study and recitation not only serves the Guru but also allows the writer to gain merit for serving God in humanity, fostering a strong devotional community.