First Person (Central Narrator), Third Person (Limited Omniscient)
Let's begin with first person, shall we? There are two different first-person narrators in The History of Love: Leo Gursky and Alma Singer.
Leo's narration—open, honest, laid bare—beautifully embodies his existence as an old man who's well past worrying about appearances. He freely admits his shortcomings and confesses his bewilderment as the mysterious events begin to unfold. Perhaps more importantly, his narration moves freely, often venturing into extended flashbacks of the most important events in his life.
Memories of the time before World War II—in Poland with his beloved—arrive so often and are presented so forcefully that it seems like he's desperately trying to keep one foot firmly planted there. These memories might be what allow him to write with such vigor and vivacity, grateful for the time he has left and for the opportunity to preserve his thoughts in writing, even if he can no longer return to them otherwise.
Contrast this with Alma Singer, whose narrative voice is every bit as confused, excited, hesitant, volatile, overwhelmed, and imaginative as we would expect a fourteen-year-old's to be. Although undeniably shaped by the turbulent events in her short life, it's clear that she's documenting her story with her future in mind. The innovative arrangement of her chapters is one great example of this focus on the future.
And now, let's turn to third-person narration to round out the bunch. It makes sense that the Zvi Litvinoff chapters are presented by a third-person narrator, since there's this Big Thing eating him up inside—he's probably not just going to tell us straight out. So, instead, we're only given access to his mind and learn his story by sort of peering over his shoulder as he moves about. There's only one exception: when Rosa discovers his secret, we momentarily step outside his point of view and view Litvinoff as his wife sees him. Tellingly, that's where their story ends—as in, the narration can't continue as it did before, now that the secret has been revealed. These narrative approaches, then, are intimately linked to the development of the characters.