A lobby is where a building makes its introduction. If it has nothing to offer but stone and elevators, it's a cold, clammy handshake. One exhausted plant in a chipped plastic pot, a buzzing fluorescent light overhead, tired carpet — it's depressing. If it's an ornate and luxurious lobby, it makes your presence seem like a walk-on role in the improvisational theater of urban life.

You don't expect them to be spectacular, but you're always a bit disappointed when they're dull. Then you forget about them: Lobbies are meant to be traveled through, not inhabited.

Minneapolis has many fine lobbies. It probably doesn't need most of them. We enter buildings on the second floor, and have for decades; lobby entrances on the street are for newcomers who don't know the mysterious warren of the skyway system. Downtown is caught between two models — the old ceremonial room on the ground floor, often inherited from the pre-skyway era, and the skyway entrance, which may or may not have anything that says "Welcome."

It would make sense to put the security guard and the information desk on the second floor and ignore the ground floor entirely, but we can't quite admit that's what we've come to. Architects still pretend the lobby is the focal point of the visitor's experience, and to be honest you'd hate to see the day when they don't.

Consider 33 South Sixth, aka the Multifoods Tower, aka that ugly square log rising above City Center. Its lobby has two faces. One side faces the interior of City Center, and while it's not the loveliest view, there's a sofa where you can sit and watch the world pass by. The other side faces the street, and it's intended to impress. Huge. Devoid of detail. Enormous ART because there must be ART. Perfect for a dystopian sci-fi movie where hundreds of identically dressed people are heading for the elevators. Pass through, quickly.

At the U.S. Bancorp building on Nicollet Mall, across from Mary Richards' WJM building, a broad window makes the mall seem like a passing parade; the escalators tie the skyway level to the lobby area. Simple, clean and effortlessly urban.

One lobby is meant to impress, enclose and process; the other encourages a lingering look.

Postwar modernist buildings loved the spare, technocratic power expressed by the Multifoods lobby, but not everyone played that game. The aforementioned RSM Plaza — the Midwest Federal building where Mary Richards worked — had no grand spaces. The pre-skyway era could give us sumptuous spaces like the elevator banks of the Medical Arts building; it could also produce the Baker Building: beloved for its repeating motifs of a woman's face on the outside, but strictly business inside, with a utilitarian elevator hall.

Occasionally, a lobby can be both restrained and playful. The former Lincoln Center, across the street from Government Center, is the 333 South Seventh Tower now. The lobby is a hard place: all business. Black-and-white stone. A triangular fountain on the wall that's so 1980s you expect to see Gordon Gekko watching it with admiration.

It's a constrained space with escalators and thick square pillars, but the view of trees and grass outside seem to double its dimensions. Artsy sofas make you think, "I should sit here someday and look at my phone while frowning, importantly." New programmable lights fade on and off in seasonal hues. The building is on the edge of the downtown core, which makes the lobby feel like a hidden treasure.

Most historic: Lumber Exchange. It's unchanged since 1888. You detect the ghosts of men with walrus mustaches and pocket watches; you expect spittoons. The boxy white marble room has few flourishes except for an ornately carved newel post on the staircase, sticking up like Louis Sullivan's thumb, and the revolving door on Hennepin. It's not original. The door was originally located between New York's Grand Central Station and the Commodore Hotel, where it opened into a room the promotional material called "The Most Beautiful Lobby in the World."

The door was removed when the Commodore was gutted and rebuilt by a fellow named Trump. A more flamboyant example of the late 19th century — a frilly dandy compared with the Lumber Exchange's solid burgher — is the lobby of the Grain Exchange. The ceilings are decorated in Louis Sullivan-esque ornamentation, imaginary organic shapes that look like the frozen spume from some otherworldly lake. The elevator doors have stylized pictures of fields and grain silos, in case anyone going in to trade wheat forgot what they were supposed to do that day.

Most Gatsby-esque: The Rand Tower. The details are perfect — the inlaid stars and moons on the floor, as if the place was built for an eccentric tycoon who loved Lucky Charms, the Art Deco zinc moldings over the elevator doors, and of course the statue. An elegant sylph named "Wings," it reminds us not only of the Twenties' vogue for speed and the great blue beyond, but the passions of the building's aviator owner, Rufus Rand. It has entirely too much staircase, but you can't help imagine Rogers and Astaire descending the marble steps. (And trip and tumble down: its unevenly shaped steps make it treacherous) It's a time capsule, unchanged, and there's something bittersweet about its beauty. You always seem to be alone. The party always seems to have ended an hour before you got there.

Maybe that's because the lobby doesn't belong to you, and you don't belong to the lobby. It's just a space. It has one true resident, and that's the person who mops the melted snow and runs the floor polisher. The only one who really cares. The rest of us, we're just passing through.

James Lileks • 612-673-7858