Why are there so many speakers in The History of Love?

The multiple speakers in The History of Love show the genuine transcendence of love, particularly by access to the story between Leopold (or Leo) Gursky and his first—and only—love, Alma. Consider the many different speakers the novel follows: these include Leo, a 15-year-old girl named Alma Singer, and Alma's brother, nicknamed Bird. The multiple perspectives allow us to see how Leo's lifelong love for Alma resonates in other times and with other people.
The History of Love is the title of Krauss's novel, but it also refers to the title of a book within the novel itself—a manuscript that was originally written by Leo but published in Spanish by his childhood friend Zvi Litvinoff. (Zvi's perspective becomes another in the novel, though he is not one of the speakers; rather, Krauss chooses the third-person omniscient narration for the sections that cover the publication of The History of Love.) The publication of the book is significant, as the reader sees it fall into different hands and influence various lives. There is a great deal of dramatic irony, as the lives of Krauss's characters are ultimately brought together by the book's existence. In the end, Leo and Alma's history of love influences people around the world.