When Holden sits down to write Stradlater's composition, all he can think about his dead brother Allie's baseball mitt, which had poems written all over it in green ink so Allie wouldn't get bored while out in the field.
We find out that Allie was incredibly kind, left-handed, and had intensely red hair.
Holden reveals that on the night Allie died (of leukemia) he slept in the garage and broke all the windows with his bare fist. He had to go the hospital afterward, and "they" wanted to psychoanalyze him.
Holden reveals that Jane is the only person whom he has ever shown Allie's baseball mitt.
After Sunny leaves his room at the hotel, Holden starts talking aloud to Allie. This, he informs us, is something he does quite frequently when he's depressed.
He keeps telling Allie to get his bike and meet him at Bobby's house, to make up for an incident from their childhood when Holden wouldn't allow Allie to play with him.
Holden remembers an episode from his youth when D.B. convinced Allie that you didn't have to be in a war to be a good war writer.
When Holden is drunk and wandering around the park in the cold, he thinks about his own potential funeral and concurrently about Allie's. He wasn't at his brother's funeral, he says, since he was still on the hospital for his hand, but D.B. told him one aunt kept saying how peaceful Allie looked.
He doesn't understand why they put flowers on Allie's grave all the time – who wants flowers when you're dead, Holden wants to know.
Mostly, Holden is bothered by the fact that Allie is under the ground, surrounded by all those other dead guys. When it rains, he says, they can all go running for cover, but Allie has to stay where he is.
When Phoebe insists to Holden that he doesn't like anything, he counters that, no, he likes Allie.
Phoebe says that shouldn't count, but Holden says you don't stop liking someone just because they're dead.
As Holden crosses the street, he worries that he might disappear. Talking aloud to Allie, he asks, "Allie, don't let me disappear," and then whenever he reaches the next curb, Holden thanks Allie.