What is the significance of writing a Guru's biography, according to the preface?

The preface explains that writing a Guru's biography is a very ancient and superior form of service. This tradition is mentioned in the Narada Purana, highlighting its ancient roots. As detailed in Chapter 0, when a devotee writes a detailed poetic biography, they are performing Guru service. Furthermore, when other devotees study and perform devotional readings (Parayans) of that work, the writer gains the merit of serving God in humanity (Jan-Janardan), and the readers also achieve the purpose of their lives. A Sadguru can accept service either by writing great works themselves or by having their life stories documented by their devotees for others to study.