Bird sneaks into Alma's room and steals her notebook, How to Survive in the Wild.
Then he pretends to be sick so he can stay home from school and spend all day finding out whom Alma is searching for.
Most of the information in the book is actually about how to survive in the wild.
Then he sees the name Alma Mereminski.
At first he assumes this means Alma wants to marry someone named Mr. Mereminski. But then he sees where it says "ALMA MEREMINSKI = ALMA MORITZ" (16.3). So he thinks maybe his sister's also in love with someone named Mr. Moritz.
He sees where Alma has written about how much she misses Misha, but it's in code so he doesn't understand it.
The only person Bird misses is his dad. He is jealous of how well Alma knew their father (though, as the reader knows, she didn't know him nearly as well as Bird thinks she did).
And then he sees in the notebook that she's written, "I FEEL SAD BECAUSE I NEVER REALLY KNEW DAD" (16.6).
But Bird is still convinced Alma definitely knew their father, David Singer, well. So he thinks maybe this means that their mother had Alma with another man, before marrying David Singer, and that that man is either named Moritz or Mereminski.
He deduces that she's trying to find her real dad.
He pretends to be sick the next day, too. This is a lot to take on.
He wonders if maybe it was Alma's dad who gave their mom The History of Love and not his own dad. He thinks that maybe the book will tell him who this Alma's dad was.
He also thinks that maybe this mysterious man was a spy, and that's why he has two last names (naturally).
He goes into the kitchen to make a peanut butter and jelly sandwich, and the phone rings.
It's Bernard Moritz (Isaac's brother, remember), asking for Alma.
Bird is surer than ever that God can hear his prayers.
Bernard is calling about the note Alma left on his brother's door. Isaac was in the hospital at the time, and he has since died.
Bernard says that, before Isaac died, his brother told him about some letters he had found in their mother's drawer, which suggested that Mordecai Moritz was not his (Isaac's) real father, and that this other man had written a book called The History of Love.
Alma had mentioned the book in her note, so he thought he'd call and let her know his brother had died.
Bird, having always been told that Zvi Litvinoff was the author of The History of Love, asks Bernard if that's who Isaac thought his dad was.
And Bernard says no, he thought it was a guy called Leopold Gursky. Bird asks him to spell it, and he writes it down. Then he asks what made his brother think this Gursky guy was his father. Bernard says that it was because he included parts of the book inside his letters.
Bird is really excited to be solving the mystery, since helping people might mean that he really is a lamed vovnik—excellent.
He is now convinced that Alma's father gave their mother the book because he wrote it. That is, he thinks Leo Gursky is Alma's father.
Then he has an idea. He looks up Leo Gursky's name in the phonebook and finds it.
He prints out a copy of his mother's translation of The History of Love, puts it in a brown envelope, and writes "FOR LEOPOLD GURSKY" on the front (16.33).
He takes $100 out of his lemonade money, puts the envelope under his jacket, and walks to Leo Gursky's house.
Then the book switches back and forth really quickly between Alma and Leo:
Alma receives a letter just like Leo's, asking her to meet him on Saturday on the benches in front of the Central Park Zoo. It's signed "Leopold Gursky," but of course both of these letters were written by Bird.
Leo waits on the park bench for a long time. He's sort of delirious, and really believes he's about to die. He says he feels like the oldest thing in the world.
Alma wonders where the letter came from, since she doesn't know anyone named Leopold Gursky.
Leo decides he's going to sit on that bench and wait, forever if necessary.
Alma thinks the letter might have been written by Misha. She really misses him.
Leo sits on the park bench and thinks about his life. Despite all that he has suffered, he still feels positive.
Or maybe, Alma thinks, the letter was from the guy at the Municipal Archives, calling to tell her something new about Alma Mereminski. Or maybe he wants to ask her out on a date. There are just so many options.
Leo remembers living in the forest during the Holocaust. He ate worms and drank water from puddles. He snuck into people's cellars and ate raw rats. He did it just to stay alive, and the reason he wanted to stay alive was for his beloved Alma.
Alma remembers there was an old Jewish man working at the City Clerk's Office. Maybe that guy's name is Leopold Gursky.
Leo remembers the first time he realized he was able to see something that wasn't really there. He was ten years old and felt separate from the other boys. He saw an elephant standing in the middle of the town square. He knew it wasn't really there, but he wanted to believe in it. That made the elephant seem real.
Alma wonders if maybe the doorman wrote her the letter—maybe he had some information about The History of Love.
Over time, Leo began imagining more and more things that weren't really there. He used to amuse his Alma by telling her about it.
Alma then thinks that maybe Isaac had written the letter himself, sending it before he died. Maybe Leopold Gursky is the name of another one of his characters—in which case, when she goes to the park, the bench will be empty.
Leo is really convinced that he's going to die on this park bench. In order to make it easy for Death to find him, he pins an index card with his name on it to his jacket. He thinks about human beings' capacity for change.
Alma arrives at the park. There are lots of people on benches, and she has no idea how to know which one is Leopold Gursky. She sits down on a bench.
Leo remembers a time he was hiding in a potato cellar when the SS (Schutzstaffel) came. One of them was telling the other about suspecting his wife of being unfaithful. He became so distraught that he was no longer hungry, and just because of that they didn't find him.
Alma sits on the bench for twenty minutes, then twenty minutes more. The only people left in the park are an old man and herself. She decides Leopold Gursky is not going to arrive after all and gets up to leave. She passes the old man, and notices the index card pinned on his chest.
Leo feels gratitude for the SS soldier's wife. He marvels that she has no idea how her decision to kiss a stranger ended up saving his life.
Alma stands in front of Leo. He barely notices her. She says, "My name is Alma" (16.76).
Leo is not quite in his right mind. He thinks it's the angel of his beloved Alma.
Alma says, "I was named after every girl in a book called The History of Love" (16.79).
Leo says, "I wrote that book" (16.80).
Alma says she's serious—it's a real book, written by Zvi Litvinoff, in Spanish, etc. She gives a brief summary of that part of the story.
Leo starts laughing, still thinking that she's some sort of apparition in his mind. He accuses her of loving Zvi, and him, and Bruno.
But then he sort of snaps out of it, realizing that Alma might actually be a real girl. So he calls out to a man walking by, asking whether there's really a girl sitting next to him. The guy says there is.
Alma asks who Bruno is. Leo admits that he doesn't really exist. He was a friend of his who died in 1941, who he's made into a character in his waking life ever since, to have someone to talk to.
Then he tells her he had a son who didn't know he existed, named Isaac.
Alma asks if he was ever in love with a girl named Alma Mereminski. Leo taps her arm twice, meaning "Yes." She asks if that Alma left for America. "Yes." She asks if his son's name was Isaac Moritz. "Yes."
Leo feels his heart leap in his chest. Alma puts her arms around him and hugs him.
The book ends the same way The History of Love within The History of Love does: with "The Death of Leopold Gursky," a poem of sorts that equates writing with love and with life itself.