It is comforting for a critic to begin a year with something he likes a lot, or even a little. So, I give you 1499 Massachusetts Ave. NW, a new apartment building on the fringe of downtown. I like it somewhere between a little and a lot.

The building is close to where I work so I've watched it go up over the past two years with much anticipation. My first reaction was simple pleasure that anything at all was being built on the site, which for decades had been a particularly dispiriting surface parking lot that marred what once must have been a pretty hill.

Then, as the superstructure began to rise, I started to worry a bit about what I wished for. The site on the northeast corner of Massachusetts Avenue and 15th Street is highly visible, and as the building climbed higher, so did my awareness of the stakes. A crummy building or even an average one would hardly render justice to the prominent location.

But before these worries went too far I began running into architect Philip Esocoff, who was in the habit of stopping by to check the progress of his design. Learning that Esocoff was in charge was reassuring, for he is a terrific architect with much Washington experience. Before stepping out on his own in 1995, he had been a chief designer for Keyes Condon Florance, a prominent Washington firm. His many credits include the altogether splendid office-retail-residential structure that enlivens the West End at 2401 Pennsylvania Ave. NW.

To paraphrase Washington architect Hugh Newell Jacobsen, every work of architecture should have an aha factor: a point at which the visitor cannot help but stop and utter, "Aha!" At 1499 Massachusetts this happened to me as the facade brickwork was nearing completion at the 12th floor, when it became clear that Esocoff had shaped his big building in a series of concave curves.

Aha: Scalloped facades. The vacant corner lot on one of the city's primary boulevards had waited years for a building with personality, and it became clear at this point that the corner was going to get what it deserved. Mind you, the scalloped fronts on both 15th Street and Massachusetts Avenue are not a superficial trick. Rather, in true Esocoffian fashion, they are parts of a thoughtful, vivid, well-ordered design.

The building wears its size well. Thanks to a transfer of development rights encouraged by the city's hotel-residential overlay zone, it rises to 15 stories -- high for this part of town. It's also quite bulky, containing 269 rental units and stretching through the block north to N Street. (The apartments range in size from efficiencies to three bedrooms and in starting monthly rents from $1,290 to an astonishing $5,175.)

Though the N Street facade is none too welcoming -- no scallops, and a couple of large openings for service vehicles -- the primary impact of this big building is strong and bracing. As you approach it from Scott Circle a block to the west, you definitely know that this building is there. It's an emphatic new landmark that stands out crisply against the sky.

You will note, however, that there's something awkward about the shape. At its northern edge the building steps back from 15th Street to accommodate a row of three handsome, if sadly maintained, 19th-century houses. As an object in the cityscape, the new building unquestionably would have benefited from the added exposure.

However, the architect says, the original developer failed in an attempt to buy the three properties. Perhaps it's just as well. Such contrasts in scale and period usually make city streets more interesting. And Esocoff handled this adjustment well, turning what could have been towering blank walls into striped masonry backgrounds for the pinnacled houses.

(That first owner, Zuckerman Gravely Development, sold the project to Post Properties, an Atlanta-based firm that specializes in upscale apartments. Hence, the building's unconvincing official name -- Post Massachusetts Avenue. Hint: Do not tell a cab driver to take you there, or undoubtedly you'll end up at the nearby Washington Post. There's no connection between the two enterprises.)

Esocoff's significant achievement with this building was to combine a sophisticated respect for Washington traditions with a commitment to freshness and modernity.

In fundamentals, Esocoff started out with the tried and true. The building facades are organized into base, middle and top, as had been done for millennia until the practice was shunned by many 20th-century modern architects. The corner is rounded, a standard device for acknowledging the odd-angled intersections caused by Maj. L'Enfant's overlay of diagonal avenues on the foursquare street grid.

The facades, like those of most Washington buildings, are made of stone and brick. As of old, this stone- and brickwork is nicely animated with changes in pattern and texture. Most of the apartments, in time-honored fashion, extend outward with glassed-in bays. The linteled windows are frames set into the masonry walls, rather than ribbons of glass.

You might expect, going over this list, that 1499 Massachusetts would be just another revivalist building, at best, or at worst a stressful collage. Yet the overall effect is at once original and cohesive. The building forces you to stop and ponder: How did the architect manage to attain such a balance?

It's clear, for starters, that the scalloped walls play a major role. There's none the like in Washington. Slightly cantilevered over the limestone base, the concave curves extend from Floors 4 through 13. They are generous in extent, measuring nearly 25 feet from end to end, giving a pleasing undulation to the facades.

The setback of the top two floors is conventional -- city regulations call for setbacks at such heights -- but the silhouette is enlivened considerably by the spray of planks for a rooftop arcade. (When the vines grow out, the building will have a green halo.) Also, orderly arrays of brick piers add distinction.

Rhythm is a key element. Each of the curves is punctured by one of those glass and metal bays -- strong vertical components in a horizontal composition. The balance is reinforced in the smaller pieces -- the courses of outsize bricks play against the tall, narrow glass panels in the bays and rounded corner.

Changes in texture and color add to the pulsation. Bands of rough-cut stone punctuate the scalloped edge of the 13th floor. Dark-light brick striping gives lively dimension to the two floors above that. The metal in the bays and window frames is painted a matte blue of medium brightness, which stands out against the field of buff-orange bricks.

I must say, I like the building least at the very bottom. The recessed limestone base reads almost like a different building from the one it supports. The principal entry sequence on 15th Street is none too appealing, what with a garage entry located right next to the front door. Nor are the public spaces inside anything to cheer about -- nice materials and warm colors frittered away in the service of a so-so postmodernist design. And though it's a nice thought, the landscaped courtyard is populated by a little convention of concrete planters that somehow managed to sneak in.

Still, in its primary, public presence this is a notable, lively, urbane building. As a spirited addition to Washington's list of "Best Addresses" -- the title of James Goode's 1988 book on the subject of Washington's apartment houses -- Esocoff's building will be around for many years. It makes a fine beginning to 2003.

The planks atop the building's rooftop arcade will eventually support a halo of green vines.Scalloped facades bring some welcome personality to Philip Esocoff's Post Massachusetts Avenue apartment building.The building's Club Room, spoiled by a so-so postmodernist design.While the first-floor courtyard at 1499 Massachusetts Avenue is too cluttered with concrete planters, the building -- and the view -- get better the higher you go.