What role do written works play in serving a Sadguru and building a following, according to the preface?

According to the preface in Chapter 0, written works are a significant form of service to a Sadguru. There are two primary ways this service is rendered: either the Sadguru creates great works themselves, or they have their biographies written by devotees. These biographies then become tools for service for the entire congregation of devotees through study and devotional readings called Parayans. The act of writing is a service, and the act of group study by other devotees is also a service that helps them achieve life's purpose and builds a strong community around the Guru's life and teachings.