What are the two primary, detailed Guru biographies suitable for Parayan mentioned in the preface, and who authored them?

The preface highlights two major Guru biographies in Maharashtra that are considered ancient, detailed, poetic, and suitable for Parayans. The first, as mentioned in Chapter 0, is the 'Brihat or Thorale Guru Charitra,' a sweet and graceful biography of Shri Samarth Sadguru Narsimha Saraswati Maharaj, written by Shri Saraswati Gangadhar. The second is the more recent 'Shri Sai Satcharita,' an inspirational and grace-filled biography of Shri Sai Baba Maharaj, authored by the late devotee Shri Govind Raghunath, also known as Annasaheb Dabholkar. The text emphasizes that no third work of such detail was commonly found.