What information does the preface provide about the various authors of Guru biographies, specifically Dasganu Maharaj and Saraswati Gangadhar?

The preface offers details on several authors of Guru biographies. As per chunk 11 of Chapter 0, Shri Dasganu Maharaj is described as a foremost modern poet who was worthy of Shri Sai Baba's grace. He authored two short but excellent and heart-touching biographies of Baba. Regarding Shri Saraswati Gangadhar, chunk 12 of Chapter 0 reveals his family lineage. His surname was Sakhare, and he was the fifth descendant of Shri Sayandev, who had received a boon from Shri Narsimha Saraswati Maharaj that his descendants would perform constant service. This provides a background on the spiritual heritage connected to his writing.