The preface mentions that a Sadguru takes service through books. Can you elaborate on the two forms this service takes and how it relates to community building?

According to Chapter 0, a Sadguru accepts service from devotees through books in two distinct ways. The first is by creating great spiritual works themselves, such as the Shri Dnyaneshwari. The second, more community-focused method, is by having their biographies written by devotees. These biographies, like the Shri Sai Satcharita, are then used for study and 'Parayans' by the congregation of devotees. This collective study not only serves the Guru but also acts as a form of public service, allowing many people to connect with the teachings and each other.