HOLLYWOOD — Two weeks ago I filed the paperwork to have Stage 7, the 1928 soundstage on a lot most of you have driven past a thousand times, declared a Historic-Cultural Monument. I stand by every word of that application. I have also come to think the building is the easy part.

I am a historian, and historians are trained to save objects: the truss, the facade, the plaster ceiling. I wrote lovingly in that application about Stage 7’s roof, its column-free span, its silent-era rigging points still bearing weight after ninety-eight years. All of it true. All of it worth protecting. But a soundstage is not a cathedral, admired for standing still. Its entire value is that it works — that it can still pretend to be a spaceship, an ocean liner, a rainstorm on command. And a stage does not work by itself. It works because people know how to make it work.

One of the crew veterans who signed my application, a retired grip, wrote that Stage 7’s floor “has more secrets nailed into it than any building in this city, and I personally nailed in several.” I have thought about that line every day since. The secrets are not in the wood. They are in him. When he goes, and he is not young, the floor is just a floor.

This is the preservation problem no landmark plaque solves. We have gotten reasonably good, in this town, at saving buildings once enough people make noise. We are catastrophic at saving the knowledge that makes the buildings mean anything. The grip who can rig a stage blind. The scenic painter who can mix a sky. The projectionist who can run a fragile print without shredding it. The costume house that knows which drawer holds a 1930s policeman. We protect the theater and let the craft that fills it walk out the stage door for a job in another state, and then we act surprised when the building becomes a museum of itself.

I have watched, in just the reporting of this paper over a single month, a costume house give away a century of knowledge because no one was left to inherit it, and crews pack rental trucks for Georgia because loyalty stopped paying rent. Those are not separate stories from Stage 7. They are the same story. A stage without stagehands is a warehouse with good acoustics.

So yes, protect the building. Give Stage 7 its monument status this fall, its plaque, its temporary shield against the wrecking ball. But understand that we will have saved a box. If we want to save what the box is for, we have to treat the people — the trades, the shops, the apprenticeships, the institutional memory carried in aging hands — as heritage worth keeping here, with the same urgency we bring to a roof truss.

I filed to save a stage. What I actually want to save is the moment the red light goes on and someone who knows exactly what he is doing makes an empty room become the world. You cannot landmark that. You can only refuse to let it leave.