Can you tell me about the author's personal story of missing an opportunity to meet a saint before he met Sai Baba?

Certainly. In Chapter 21, the author, Hemadpant, recounts his own experience to illustrate the principle that one only encounters saints when good fortune dawns. While he was serving as a Magistrate in Bandra, there was a famous Siddha named Pir Maulana whom many people of various faiths visited. The Siddha's servant, Inus, repeatedly urged Hemadpant to come for his vision. However, due to pride and what he calls "ill-luck," Hemadpant resisted, thinking, "Why should I go? Should I be pressured by others and lose my own prestige?" He never went for the vision and was eventually transferred. He uses this story from his past to show that proximity is not enough and that without divine grace, such a meeting is not possible.