One year ago, the excellent Web log Curious Expeditions (curiousexpeditions.org) posted a long series of color photographs of some of the world’s most beautiful libraries. Among them were Strahov Theological Hall, the Beatus Rhenanus Library in Basel, Biblioteca Angelica in Rome, Duke Humphrey’s Library in Oxford, the Boston Public Library, the extraordinary Peabody Library in Baltimore, the Melk Abbey Library in Austria, the Beinecke Rare Book and Manuscript Library in New Haven — 93 pictures in all, of nearly as many libraries.

Seldom has bibliophily seemed so like pornography.

The site’s proprietors invited readers to suggest other great libraries not mentioned in the post. I suggested the library of the Brooklyn Historical Society. It is the most beautiful, if not the grandest, library in New York, and one of the city’s most beautiful rooms of any kind.

The Long Island Historical Society was founded in 1863 by several august Brooklyn gentlemen in rooms at the Hamilton Literary Association, on Court Street at Joralemon Street in downtown Brooklyn. (The society changed its name to Brooklyn Historical Society in 1985.)

The society’s purpose was to collect any and all documents — books, newspapers, pamphlets, maps, pictures, ephemera — related to the history of Brooklyn, and to offer public lectures on historical topics. As local historical societies sprouted across America in the 19th century, Brooklyn’s — serving the country’s third-largest city — was among the most flourishing.

The Court Street premises accommodated the collections, but lectures had to be held off-site. Often, the Brooklyn Academy of Music, then around the corner on Montague Street, was pressed into service by the society. It made sense to have everything under a single roof.

The society acquired a lot on the southwest corner of Pierrepont and Clinton streets in Brooklyn Heights. An 1878 architectural competition yielded a winning design by a then 41-year-old named George Browne Post. Post wasn’t new on the scene. Trained as a civil engineer, he’d worked for Richard Morris Hunt and served as an officer in the Union Army before forming his own practice. His Williamsburgh Savings Bank, the great-domed edifice (now HSBC) on Broadway at Driggs Avenue in Williamsburg, went up in 1875, and was one of its decade’s most important buildings in New York.

Still, most of Post’s major commissions — the Produce Exchange, the New York Stock Exchange, the City College campus — lay in the future. For me, Post’s greatest works — they are also among New York’s greatest works — are his buildings at City College in Hamilton Heights, and the Brooklyn Historical Society.

In his design of the society’s building — which included an auditorium, a library, a gallery, and offices — Post innovated dramatically. On the outside, he was among the first American architects to experiment with ornamental terra-cotta. Of particular note are the terra-cotta heads modeled by the outstanding sculptor Olin Levi Warner. Look for the likenesses of Columbus, Benjamin Franklin, Shakespeare, Gutenberg, Beethoven, and Michelangelo. Between 1999 and 2003 the society operated off-site as its building underwent a painstaking restoration. The façade had, in all the building’s history, never been cleaned. The restorers had to be as meticulous as Post had been in his choices of brick, stone, terra-cotta, and mortar to achieve a radiant spectrum of browns and reddish-browns. Over the years the exquisite coloration had worn away; it’s back, and it’s beautiful.

The architectural historian Sarah Bradford Landau, in her monograph on Post, suggests that the Palais de l’Industrie, built for the Paris Exposition of 1855 (and since demolished), may have influenced Post’s design. I myself see in the society’s design more than a little of Post mentor Hunt’s Lenox Library (1870-77), which was on Fifth Avenue at 70th Street, where the Frick Collection now stands. In the end, there’s no other building like it in New York.

From the outside, you can clearly see that the second floor, higher and more elaborately articulated than the others (three plus attic), is mostly what the building’s about. This is the Othmer Library, our greatest repository of Brooklyniana and of much more.

Post, the engineer, created a dramatic double-height, galleried space. The cast-iron columns in the first-floor auditorium support the library floor, while iron trusses in the attic support the library ceiling, the attic floor, and the roof. The loftiness of the space and its exquisite woodwork take your breath away. The gorgeous carved-wood fluted columns, with Corinthian capitals, encase iron columns that support the galleries that encircle the room. It is everything a library should be.

A library exists to feed your brain. Nothing says it can’t also melt your heart.

fmorrone@nysun.com