What are the two main detailed Guru biographies mentioned in the preface, and who wrote them?

The preface identifies two significant, detailed, and poetic Guru biographies suitable for devotional readings like Parayans. The first is the "Brihat or Thorale Guru Charitra," a sweet and graceful biography of Shri Samarth Sadguru Narsimha Saraswati Maharaj, which was written by Shri Saraswati Gangadhar. As detailed in Chapter 0, the second major work is the "Shri Sai Satcharita," a recent, inspirational biography of Shri Sachidanand Samarth Sadguru Sai Baba Maharaj, authored by the late devotee Shri Govind Raghunath, also known as Annasaheb Dabholkar.