Symbolism, Imagery, Allegory
The title of the novel, Other Voices, Other Rooms, is a little mysterious. There are some clues to explaining it, however, in one of Joel's favorite methods of escaping the terror of the present. When he is very unhappy with what's going on around him, he just leaves—in his mind.
Once, when Amy freaks out and spins into a repeating frenzy,
Joel went all hollow inside; he thought he was going to wee right there in his breeches, and he wanted to hop up and run [...] So he […] tried with all his might to find the far-away room. (1.4.50)
Wait, what? Yeah, it's kind of weird. But later on the narrator explains further.
Amy says she hopes she hasn't upset Joel, but he's far away, in his imagination:
But the walls of Joel's room were too thick for Amy's voice to penetrate. Now for a long time he'd been unable to find the far-away room; always it had been difficult, but never so hard as in the last year. So it was good to see his friends again. (1.4.54)
Joel has created an entire gang of friends in his mind—some real, some imaginary—that help him to escape when life is too much for him.
Joel seems to understand each person as their own house. He has secret rooms where he can escape to; others search through rooms for their heart's desire. When Miss Wisteria searches for him in the old house the rooms she moves through are literal, but also mental:
He owned a room, he had a bed, any minute now he would run from here, go to them. But for Miss Wisteria, weeping because little boys must grow tall, there would always be this journey through dying rooms until some lonely day she found her hidden one, the smiler with the knife. (2.11.29)
In the first sentence Joel might be talking about his physical room at the Landing, where he can escape to, or his far-away room, his imagination, which is also an escape. But in the description of Miss Wisteria, the idea of "dying rooms" seems more figurative; perhaps it has to do with the passage of time, as the boys she loves grow old and leave her trapped in a child's body. And her hidden room, unlike Joel's happy place, is a final, violent death.