A GIFT was always waiting for me last summer at the 14th Street subway station, of all places.

Emerging from chemotherapy infusions every other week at St. Vincent’s Comprehensive Cancer Center nearby, I felt as if a toxic pall had descended on me.

The pall would lift a bit, however, when I spotted the little man with the big money bag sitting quietly on the uptown platform as the Eighth Avenue trains barreled by. Without fail, he would be dressed smartly in top hat, bow tie and well-polished shoes, which dangled over the edge of the bench because his legs were so short.

He was so many things I needed to be at those moments. Calm. Patient. Trusting. Unselfconscious. And doughty, in his own chin-up way.

Best of all, he made me laugh.

So did his co-conspirators overhead and underfoot, like the alligator emerging from a manhole to drag a victim into the sewer, another one of the dozens of delightful bronze figures by Tom Otterness in an ensemble called “Life Underground.”

It is one of about 170 works of permanent public art commissioned since 1986 by the Metropolitan Transportation Authority for its subway and commuter rail stations, typically using 0.5 to 1 percent of a station’s rehabilitation budget.

On a civic level I had long admired the generosity behind the authority’s Arts for Transit program. Last summer, as I came to depend on “Life Underground” for a bit of cheer on otherwise cheerless days, I realized that the gift was for me too.

Mr. Otterness worked hard to find creative ways to place his sculpture, navigating around the rules of station design. There was no way, for instance, that a duly designated seating space was going to be given up for an artwork. So a sympathetic M.T.A. employee suggested adding an extra bench, above and beyond the number required on the platform, to accommodate the little man.

Sandra Bloodworth, the director of Arts for Transit, said the involvement of the agency’s stations department, its architects and engineers and its system safety experts has been critical. “The end goal is how we make this a better station for the public,” she said. “When you introduce art into this environment, the message is, ‘Somebody cares about this place’ ” — and, by extension, the people who use it.

A decade ago Ms. Bloodworth described the art offered by the program as on a par with any museum. Today she promotes the transit system as a public art institution in its own right, with a roster that includes Vito Acconci, Romare Bearden, Eric Fischl, Robert Kushner, Jacob Lawrence, Sol LeWitt, Roy Lichtenstein, Maya Lin, Mary Miss, Elizabeth Murray, Dennis Oppenheim, Faith Ringgold, Alison Saar and Robert Wilson.

“I now feel this is worthy of being the destination,” Ms. Bloodworth said one morning last month. “It is the museum.”

She spoke while walking the 115-foot length of Al Held’s undulating mural “Passing Through,” in the Lexington Avenue-53rd Street station. The energy of the passing crowd found an abstract echo in the intense color of the mosaic glass tiles, spheres and rings, checkerboard boxes and slabs, orange pipes and yellow clouds.

“Al Held is not only with the corporate collectors up above,” Ms. Bloodworth said, referring to the various headquarters towers overhead. “He’s here with the people.”

Four visitors from Poughkeepsie, N.Y., on their way to the Museum of Modern Art, fixed their eyes on the mural and would not let go — their necks craned and heads swiveling — even as the escalator pulled them down toward the E and V train platform below.

“That’s why we do it — right there,” Ms. Bloodworth said.

The entrance fee for this museum is just a train fare. But the distance between galleries, up to 180 miles, can be daunting.

A new $45 alternative for the armchair traveler is the 215-page catalogue raisonné, “Along the Way: M.T.A. Arts for Transit,” by Ms. Bloodworth and William Ayres, published by the Monacelli Press.

If you’re a New Yorker of a certain age, the idea of a coffee-table guide to contemporary artwork in the subway system may strike you as wildly improbable.

But “Along the Way” shows just how abundant the permanent artwork has become. It highlights nearly 70 installations, organized by artist, followed by illustrated thumbnail descriptions of every project.

The book’s chief drawback is that it is too large to use comfortably as a ride-around guide. For that, the M.T.A. has published “Art en Route,” a 50-page booklet pinpointing the artworks by train line. It is available at the New York Transit Museum stores or by request at the Arts for Transit Web site, mta.info/mta/aft, where there is also an engaging interactive guide to the collection.

Of course the subway system was born with art within it: decorative ceramic plaques and mosaic wall panels. Their durability was time-tested by a century of use and abuse. Bronze, steel and faceted glass have been added to the repertory by the Arts for Transit program, but ceramics and mosaics are still the preponderant medium.

One ceramic installation, Margie Hughto’s “Trade, Treasure and Travel” in the Cortlandt Street R and W station, emerged unscathed from the destruction of Sept. 11, 2001. It is sure to be one of the most evocative works in the subway system when it is reinstalled in the Fulton Street Transit Center, now under construction. Intended for a 60-foot-long passageway leading to the World Trade Center concourse, Ms. Hughto’s work is composed of 10 relief murals, strongly influenced by the Ishtar Gate of Babylon and meant to evoke an archaeological treasure house.

But there were contemporary references too, like panels depicting the trade center, with the Brooklyn Bridge in the foreground and, behind one tower, what once would have been unmistakable as a cumulus cloud but now cannot help look like a plume of smoke.

The World Trade Center seems at first to be absent from Ellen Harvey’s “Look Up, Not Down,” at the Queens Plaza station on the E, G, R and V lines. These floor-to-ceiling mosaic murals depict the skyline of Long Island City, Hunters Point and Manhattan, as if the viewer were suspended in air directly over the subway station.

Ms. Harvey agonized in 2002 over whether to include the trade center. “It seemed so sad to leave it out altogether,” she said.

The panorama above the Manhattan-bound platform shows the Empire State Building, Chrysler Building, Trump World Tower, Citigroup Center, Queensboro Bridge and Ravenswood generating station to the west.

On the mezzanine outside the turnstiles is the clock tower of the old Bank of the Manhattan Company building on 41st Avenue, pointing to the northeast. That would mean the view on the opposite wall — the Eagle Electric Manufacturing Company plant, the Long Island City Courthouse and the Citigroup skyscraper at Court Square — must offer a distant glimpse of the Lower Manhattan skyline to the southwest.

I looked at the scene and looked at it again. There was no trace of the towers. (But then, why should there be? The murals, after all, depict a moment five months after the attack, which explains why so many American flags are flying.) I turned around once more, to get my bearings before heading home.

That’s when I saw it: a four-inch circle of white mosaic tile, almost impossible to discern in the mural’s hazy white sky. It was the sun, directly over the place where the twin towers stood, perhaps the subtlest 9/11 memorial in New York City. And a gift waiting to be found.