What is Guru service, and are there different types discussed in the teachings?

Guru service is a multifaceted practice. As Chapter 0 explains, citing Dnyaneshwar Maharaj, serving saints with your entire being is the doorway to knowledge. This service can be categorized into worldly and spiritual types. Worldly service, such as writing biographies of great politicians or writers, is considered temporary and rooted in self-interest, yielding no spiritual fruits. Spiritual service, like writing biographies of many saints, is more beneficial but can be partial. The highest form of service is writing and studying the biography of one's own Sadguru, which can be done for selfless liberation (Nishkam) or for worldly desires (Kamya), with the selfless path always being superior.