What are the different types of Guru service, and which is considered spiritually beneficial?

Guru service, a path to spiritual knowledge, can be categorized into worldly and spiritual types. As explained in the preface in Chapter 0, worldly service includes writing biographies of great figures like politicians or historians. While this may serve the public, its importance is limited by time and it does not yield eternal spiritual fruits because it is often rooted in self-interest. In contrast, spiritual Guru service, such as writing the biographies of saints, is aimed at attaining the ultimate spiritual goal. The highest form of this, according to Chapter 0, is writing the biography of one's own Sadguru and studying it with devotion, as this is a selfless act that leads to salvation.