What are the different ways a Sadguru accepts service from devotees through books, and how does this relate to community development?

According to the preface in Chapter 0, a Sadguru takes two types of service from devotees through literary works. The first is when the Guru themselves authors a great work, like the Shri Dnyaneshwari. The second, which is highly relevant to community building, is when the Guru has their biography written by devotees. This act accepts service from both the writer and the larger congregation. The text explains that when devotees study and perform Parayans of such a biography, they are not only serving the Guru but also engaging in a collective spiritual practice that helps them achieve their life's purpose, thereby fostering a strong and purposeful community.