I'm trying to understand the book's perspective. Why isn't a widely recognized saint like St. Francis of Assisi mentioned at all?

That's an insightful question. The Shri Sai Satcharitra focuses less on creating an exhaustive list of saints and more on the core principles of spiritual practice and the Guru-disciple relationship. Chapter 19 explains this focus by stating, "'Ye yatha mam' (As they approach me...)" which places the responsibility for spiritual progress on the devotee's own actions and devotion. The text emphasizes that breaking down the "sense of difference like 'I and Thou'" is key to reaching a state of non-duality. Therefore, instead of cataloging many saints, the book provides lessons intended to help the seeker directly, with Chapter 19 noting, "As the action, so the hearing; as the practice, so the benefit; this is the secret of this chapter."