HOLLYWOOD — The oak tables are back within an inch of where they stood in 1927, and the reference staff spent last week convincing regulars that the room behind the rope was open again.

The Hollywood branch library on Ivar Avenue reopened its main reading room on Monday after a nineteen-month seismic retrofit, restoring a high-windowed space that generations of students, screenwriters and people with nowhere warmer to sit had used until the engineers closed it.

The work was mostly invisible, which was the point. Crews threaded steel bracing inside the original walls and set the ground floor on isolators meant to let the building sway a few inches in a large earthquake rather than crack. The plaster ceiling was documented, removed, and put back. The reading lamps were rewired. A water stain that patrons had for decades insisted resembled Alfred Hitchcock’s profile was, to some disappointment, painted over.

“People asked about the stain more than the earthquake work,” said Priya Raman, the branch manager. “I had to promise three separate men that we photographed it first.”

The room’s centerpiece is a thing the library no longer needs. The card catalog — a wall of small oak drawers, each with a brass pull and a typed label — has not been used to find a book since the 1990s. It was slated for storage. Instead the branch had it cleaned and kept it, in place, as furniture.

The drawers now hold other things. One bank of them has become a seed library: labeled envelopes of tomato, basil and marigold that patrons may take and, ideally, replace at harvest. Another holds bookmarks and the branch’s lost-and-found. A drawer marked “Ea–Fi” holds nothing but a single yellowed card someone slipped back in as a joke, stamped with a due date in 1974.

Not every visitor knew what it was. A teenager doing summer-school reading opened a drawer looking for a phone charger, found the seeds, and asked Raman what the little cards had been for. She explained. He said it seemed like a lot of steps.

An older patron, Delia Okonkwo, who first used the room as a girl in the 1950s, ran her thumb along the labels until she found the drawer where she had once looked up her library number. “I learned the alphabet backward standing here,” she said. “The A’s are still on the left. That’s all I wanted to know.”

The retrofit ran four months over schedule and something over budget, figures the city library system declined to itemize on opening day. Raman said the reading room’s hours would return to their old six-day schedule by August, once the branch hires back the two positions it lost while the room was dark.

The catalog stays. Raman has posted one rule on the seed drawers, set in the same small type the library once used for call numbers: take what you will plant, and bring some back.