According to Chapter 2, what other texts about Sai Baba's life and teachings existed before the Sai Satcharitra was written, and why did the author feel another book was necessary?

Chapter 2 acknowledges several existing works containing stories about Sai Baba. These include two books by Das Ganu, "Bhakta-Lilamrut," which describes Sai's life in three chapters, and "Santa-Kathamrut," which contains a knowledge-story from Sai in its 57th chapter. Other mentioned sources are Raghunath-Savitri’s Bhajanmala and works by Gujarati devotees Amidas and Bhavani Metha. Despite these, the author justifies this new text by comparing Sai's life to a "vast ocean, an infinite mine of jewels," implying the stories are countless and any collection can bring peace and enthusiasm to devotees.