BROOKLYN'S BEST AND BRIGHTEST; A Borough Filled With Brilliant Gems of Urban Architecture

It is over the bridge or through the tunnel, but in some ways Brooklyn is more entitled than Manhattan to call itself the heart of New York. This is, after all, the borough more New Yorkers live in than any other; it stretches from the gracious brownstones of the Heights to the sprawling slabs of Starrett City, and in between are neighborhoods of such vivid character as Park Slope, Red Hook, Flatbush and Williamsburg. Brooklyn has become more and more important to the city's cultural life, and its renewed neighborhoods are now more richly diverse than ever before. On pages C24 and C25, several Times writers explore Brooklyn on the rise.

BROOKLYN does not possess Manhattan's skyscrapers, or its great treasure-trove of cast-iron industrial architecture, or its intensely vibrant street life. But it is probably New York City's richest borough in terms of sheer volume of good architecture. There are more fine rowhouses, more fine churches, more fine workaday buildings in Brooklyn than in any other part of New York. They sit amid a borough that is a patchwork quilt sociologically as well as architecturally; Brooklyn has some of the city's worst slums as well as some of its finest residential neighborhoods, and the two are often side-by-side or separated only by a thin slice of in-between territory. There are vast reaches of Brooklyn's sprawl that are banal, and others that are as honkytonk as anything in New York. But there are other sections that, architecturally at least, can rank with any residential neighborhood in any city in America.

While it is houses that really make Brooklyn - row after row of townhouses, in every style the 19th century dreamed of, stretching on in a way that seems implausible to a Manhattanite -Brooklyn also possesses some splendid public architecture, some of it unique in the City of New York. What follows is a look at 10 places, all of which are Brooklyn's own - buildings, or places, that offer some kind of architectural experience that neither Manhattan nor any other borough can equal.

Totally Brooklyn's own, and virtually a symbol of the neighborhood of Brooklyn Heights, is the Esplanade, the promenade behind Columbia Heights that overlooks New York Harbor. This is arguably the greatest view in all New York; it is all of lower Manhattan, looking far more spectacular from here than it ever can from Manhattan island itself.

The Esplanade is really a roof deck made into a public park, covering the Brooklyn-Queens Expressway, and it is the most successful merging of city and highway anywhere in New York. It is not the first such effort - the riverfront promenade of Carl Schurz Park that extends over the F.D.R. Drive was finished in 1938, 13 years before this one - but it is the best. Brooklyn Heights, itself one of the city's very greatest townhouse neighborhoods, merges gracefully and naturally onto the Esplanade, which functions as a park, a viewing spot, and as a central anchoring space for the neighborhood. It feels as if Brooklyn Heights, with its tight streets, were all one great building and the Esplanade were its veranda.

There are firehouses all over New York, and many of them are first-rate works of architecture, but none is quite like the old City of Brooklyn fire headquarters in downtown Brooklyn at 365 Jay Street, designed by Frank Freeman and finished in 1892, six years before Brooklyn was merged into the City of New York. This is perhaps New York's greatest Romanesque Revival building, and it is by Brooklyn's best 19th-century architect; from afar it recalls the work of Henry Hobson Richardson, and from close up, the ornament shows Freeman's debt to Louis Sullivan.

To call this building robust is an understatement. It is strong and sensual; its deep arch and rounded columns suggest that Freeman knew civic power and civic graciousness need not be incompatible. It is too derivative to be called truly original, but it is no less wonderful for that -this noble building seems to reach out and give us a bear hug, reminding us that public architecture can be both monumental and friendly. Beaux-Arts Bank

Not far away, at the intersection of Fulton Street and DeKalb Avenue, stands another essay in civic grandeur, the Dime Savings Bank. There are other splendid, Beaux-Arts-influenced banks elsewhere in New York, including some other good ones in Brooklyn, such as George B. Post's wildly energetic Williamsburgh Savings Bank of 1875 in Williamsburg. But none is quite like the Dime, which was built in 1907 to the designs of Halsey, McCormick & Helmer, for no other grandiose bank teaches us so fine a lesson in urban design.

The block the bank occupies is three-sided. It is not easy to build a triangular classical temple, but the architects did it, with such ease that one would have assumed it was done this way in Rome. The trick was to slice off the corners, giving the bank a front right on the main triangular intersection. Inside, the main banking hall is an uneven hexagon, with three short sides and three long ones. It is all pulled together by a central dome, surrounded by Corinthian columns on which have been placed immense plaques of silver dimes. There are few interiors in New York as monumental yet as welcoming and uninhibiting - these architects knew something about how to make big rooms relate to human scale. And finally, once you have absorbed the joy of the space itself, look at the marble benches on which have been carved quotations. The oddest, given its placement in a bank, is from Shakespeare: ''Neither a borrower nor a lender be.''

The Fulton Ferry neighborhood, the area of industrial buildings tucked under the Brooklyn Bridge, has been undergoing a great revival in the last few years. After the Brooklyn Bridge itself - which is, of course, Brooklyn's very greatest work of architecture, but one which it must forever share with Manhattan - the most important buildings in the area still await restoration. They are the Empire Stores, the blocks of somber brick warehouses on Water Street between Dock and Main Streets, built in 1870 and 1885 by Thomas Stone.

If the Jay Street firehouse can be said to possess a kind of enveloping monumentality, and the Dime Savings Bank a dignified, slightly cooler monumentality, here is brooding monumentality. These buildings, with their closed shutters covering rows of arched windows, have a deep, quiet rhythm to them; they speak to us with a soft, dark power. To ponder them is less to think about architecture than it is to have an experience similar to looking at the dark paintings of Mark Rothko. These buildings have been saved as part of a state park that will keep the riverfront of this section in the public domain, and they await restoration. Model Housing

Brooklyn is not usually the place that comes to mind when the talk turns to utopian ideas, but the borough is home to one of the city's most important pieces of model housing: the Tower Buildings, between Hicks, Baltic and Warren Streets in Cobble Hill. Along with the adjacent Home Buildings, this complex of 226 apartments and 34 cottages built around a central rear open space was created between 1877 and 1879 by Alfred Tredway White, a businessman who set out to improve the lot of the city's tenement dwellers.

In an age when the average tenement apartment was virtually without light and fresh air, the apartments in the Tower Buildings represented a spectacular advance. White's low-rent buildings, which were designed by William Field & Son, pre-date public housing by two generations - they were a case of a private philanthropist deciding to build not for maximum profit, but for the public good. The buildings remain in good shape, their brick handsomely painted a deep red, and they stand today not only as a physical anchor in Cobble Hill, but as a reminder to all of New York of a time when an individual with capital and a social conscience could actually make some difference in the city's housing crisis.

Not as philanthropically oriented as Alfred Tredway White, but just as concerned with the quality of urban life, was Richard Butts, the land surveyor who laid out Carroll Gardens in the Red Hook area of South Brooklyn in 1846. This is a set of brownstone streets as they ought to be - in neat, even rows, tightly one beside the other, but placed way back from the street behind gracious, well-planted front yards. It was Richard Butts's idea, backed up by the developers who put up these blocks, that it was possible to merge urban density with landscaped streets, and this Carroll Gardens does better, surely, than any other place in New York.

This really is a case of having one's cake and eating it, too - of being able to have a street that is both surburban and urban. The best blocks of Carroll Gardens possess the lush landscaping of a venerable suburban avenue and the energetic, communal feeling of a good urban street. Eleven blocks were laid out in this special manner in Carroll Gardens, which was built up between 1859 and 1884; they run from First Place through Fourth Place between Henry and Smith Streets, and along President, Carroll and Second Streets between Smith and Hoyt Streets. Here, as at the Tower Buildings, private real-estate developers showed that making a profit was not incompatible with the idea of creating a better grade of housing and improving the quality of life in the city. Sumptuous Brownstones

So far as row houses are concerned, the block of South Portland Street, between Lafayette and DeKalb Avenues in the heart of Fort Greene, is nearly as special. The layout is not innovative this time, but the houses are far better - truly grand-scale Italianate brownstones, larger and more sumptuous not only than most of their Brooklyn neighbors, but than most of their Manhattan counterparts as well.

Fort Greene as a totality is not as splendid as Park Slope, which is probably Brooklyn's most consistently first-rate brownstone neighborhood. But this particular block is close to intact, and many of its houses have been restored over the last decade. More striking than any individual house, though, is the sense of ensemble - this block is very long, longer than most in Brooklyn or Manhattan, and the vista of brownstones down its great length has a striking power to evoke a sense of idealized urban memory. The huge sycamore trees that arch graciously over the street visually enrich South Portland still more, and make the street a true allee.

Perhaps it is that Brooklyn is where the whole idea of the urban street was thought through more carefully than in Manhattan - surely the ample space of Brooklyn made it possible to innovate more easily. Brooklyn is also home to two of Frederick Law Olmsted's greatest visions of urban design, Eastern Parkway and Ocean Parkway, both intended to bring monumental grandeur to the lives of the average urban dweller. Although Ocean Parkway, which runs to Coney Island, is today in better condition, Eastern Parkway, extending eastward from Grand Army Plaza, was the grander in conception.

Today Eastern Parkway is a curious mix of the monumental and the mundane - the Beaux-Arts richness of the Brooklyn Museum is on it, but so are numerous apartment houses and row houses of more ordinary stripe and, particularly as one moves farther east, plenty of dreary commercial buildings. The parkway now reflects the diverse ethnicity of the Crown Heights neighborhood beside which it passes - West Indian and Hasidic primarily, with predominantly black Bedford-Stuyvesant nearby. It is New York's first truly noble boulevard. Planned Community

One of the great surprises of the New York cityscape is Prospect Park South in Flatbush - 15 blocks' worth of rambling, turn-of-the-century houses that together constitute one of the first planned suburban communities anywhere. Once again, Brooklyn seems to have inspired a real-estate developer to create an idealized project within the confines of the commercial marketplace; in this case the guiding figure was a developer named Dean Alvord, who in 1889 envisioned a place in which ''people of intelligence and good breeding'' might find comfortable, esthetically pleasing homes reasonably close to downtown Brooklyn and Manhattan. Alvord laid out Prospect Park South with wide streets, in some cases with malls down the middle; he ordered trees planted at the property line just inside the sidewalk, creating the illusion that the streets were as wide as boulevards.

He put utility lines into the ground, a dramatic advance for his time, and ordered design guidelines to assure that the houses, which tend toward the Queen Anne and Shingle Style, be roughly consistent architecturally. Gateposts mark the entrances to the community along its bordering streets - Church Avenue, Beverly Road and Coney Island Avenue; within are such splendid blocks as Albemarle Road, with several stately mansions, and Buckingham Road. Prospect Park South remains, visually at least, as serene and apart from the urban tensions of central Brooklyn as ever.

Green-Wood Cemetery is itself one of New York City's most impressive public open spaces, and in Brooklyn only Prospect Park is arguably better. But even Prospect Park, which the designers Frederick Law Olmsted and Calvin Vaux believed superior to their own Central Park in Manhattan, does not have an entrance like that to Green-Wood. There is no gate in New York like Richard Upjohn's Gothic gateway to the cemetery on Fifth Avenue near 25th Street; there are few gates like it anywhere. It is a monumental arch, a garden gate, and a means of passage to a very separate world, all in one.

Upjohn's Trinity Church at the head of Wall Street in lower Manhattan of 1846 is a fine, but rather dry, Gothic church; it is as if he saved his energy for the Green-Wood gate, which was built in 1861. Some of the visual pleasure here must come from the unusual sight of a freestanding Gothic portal, for we are accustomed to seeing such Gothic details as a facade, not standing on their own. But it is more than that: this structure marks the triumphant moment of the Gothic Revival style in New York, the moment when the exuberance of Victorian architecture had arrived but the discipline of early Gothic Revival had not yet been lost.