Why does the author of the Sai Satcharitra invoke Goddess Saraswati, and how is she identified with Sai?

The author invokes Goddess Saraswati in Chapter 1 because she is the Goddess of Speech, knowledge, and literature, and her grace is considered essential for writing the book. The text questions how any literature could be achieved without the mercy of the Mother of the World. She is described as holding the Brahma-veena and riding a swan. The author prays for her to make him an instrument to share Sai's life story. Significantly, Chapter 1 reveals a deeper truth by stating that Sai himself is Goddess Saraswati, holding the Omkara-veena and singing his own life story for the salvation of his devotees.