An exceptionally large number of art museums seem to be dedicating newly expanded facilities these days, but few will outdo the dramatic effect of the new Gail and Melvin Nessel Wing of the Norton Museum of Art. The expansion, opened to the public in March, increases the Norton’s gallery space by a whopping 75 percent, making it the largest art museum in Florida. In the months since the opening, attendance has increased by 200 percent, according to museum officials.

The 42,000-square-foot project, which brings the total size of the museum to 112,500 square feet, provides much needed space in which to display the Norton’s fine and expanding collections of American, Chinese, European and Contemporary art and photography. The museum also hosts a series of special exhibitions each year.

The southwest wing features a free-form, cantilevered spiral staircase, a soaring three-story oval atrium, 14 new galleries, an elegant enclosed courtyard and a glass ceiling installed by Dale Chihuly.

Much of the credit for the ambitious expansion goes to museum director Christina Orr-Cahall, whose vision, drive and fundraising skills, along with a supportive and generous board of trustees, made the large capital campaign a success. Orr-Cahall recently reported that 75 percent of the goal of $35 million (including endowment enhancement) has been raised. The two-year building project, she announced proudly, is “on time and on budget.”

The new wing was designed by Chad Floyd of Centerbrook Architects and Planners of Centerbrook, Conn. His firm was already responsible for a $30 million, 77,500-square-foot expansion and renovation of the Norton that was completed in 1997. Floyd also designed the much-admired Kreible Gallery at the Florence Griswold Museum in Old Lyme, Conn.

Currently on view (through August 24) is a highly entertaining exhibition, “The Human Comedy: Portraits by Red Grooms.” The 75 paintings, sculptures and works on paper demonstrate the sense of humor and fertile imagination of the artist in colorful, animated likenesses of Mae Wet, Charlie Chaplin, Elvis Presley, Pablo Picasso, Salvador Dali, Jackson Pollack and others, as well as members of his own family.

The Nessel Wing consists of three levels of galleries housing portions of the Norton’s permanent collection. Four galleries on the first level display contemporary art and photography, such as images by Henri Cartier-Bresson, Walker Evans, Lewis Hine, Man Ray, August Sander and Edward Steichen.

The second level exhibits the museum’s impressive Chinese art collection. Highlights include a Seventh Century “Colossal Head of a Buddha” and a Shang dynasty, Twelfth-Eleventh Century BC, “Ritual Wine Pouring Vessel (Guang).”

On the third level, five galleries are devoted to selections from the Norton’s trove of European art before 1870. Here one finds works ranging from Peter Paul Rubens and Lucas Cranach the Elder to Gustave Courbet, Sir Thomas Lawrence and Sir Joshua Reynolds. Centerpieces are two enormous oils: a 90- by 62-inch Florentine masterwork, “Madonna and Child Enthroned with Saints Jude, Simon, Zelotes and Young John the Baptist,” 1586, by Giovanni Maria Butteri, and a Lucas Giordano altarpiece, “The Immaculate Conception,” 1657, measuring 787/8 by 591/4 inches.

The Norton’s Main Building is now freed up to exhibit European art after 1870, American art and special shows. The heart of Ralph Norton’s original collection, post-1870 European works, is arranged thematically in four galleries. Among the standouts are Claude Monet’s evocative “The Moreno Gardens at Bordighera,” 1884, and Paul Gauguin’s idiosyncratic “Christ in the Garden of Olives,” 1869.

An entire wall features an impressive selection of Cubist still lifes, including “Le Journal,” 1916, by Juan Gris, “La Guitare,” 1917, by Pablo Picasso, and “Still Life on Red Tablecloth” by Georges Braque. Other painters represented in the European display: Bonnard, Cassatt, Cézanne, Chagall, Dufy, Klee, Leger, Matisse, Miro, Modigliani, Pissarro, Renoir and Roualt.

Sculptural highlights include Constantin Brancusi’s sleek “Mlle Pogany II,” 1925, and Jacques Lipchitz’s “Rescue II,” 1947, created after the artist moved to the United States. Other top sculptors represented are Archipenko, Degas, Moore and Rodin.

Five galleries are devoted to a comprehensive selection of American artworks, representing a virtual “Who’s Who” of our next important Nineteenth and Twentieth Century painters. Among the earliest paintings on view are canvases by Homer and Inness, and an atmospheric Thomas Moran oil, “Florida Scene,” circa 1878, set around Fort George, near the mouth of the St John’s River. An early Twentieth Century highlight is Childe Hassam’s brilliant and colorful “Gloucester Harbor,” 1908.

There are strong paintings by artists linked to the Ashcan School, including Bellows, Henri, Luks, Shinn and Sloan. American Modernists are particularly well represented, with works by Demuth (“After All”), Dove (“Power Plant II”), Hartley, Marin, O’Keeffe and Prendergast,

Works of more recent vintage include oils and watercolors by such important figures as Avery, Lawrence, Louis (“Autumnal”), Motherwell and Noland. Jackson Pollack’s “Night Mist,” 1945, is a sizable transitional work created when he was moving from Cubist figuration to abstract images.

Andy Warhol’s familiar “Flowers,” 1964, an acrylic silkscreen on canvas, is one of many versions on this subject produced by the artist and his associates.

Also in the collection is a watercolor of a Florida beach by 20-year-old Andrew Wyeth, “Pirate Country,” 1937, created by the artist, who did not visit the state until two years later, from his imagination. It reflects Wyeth’s deft watercolor touch.

The American collection also contains a number of good pieces of sculpture by Calder, de Creeft (“Alice”), Hanson, MacMonnies and Manship.

The Norton has come a long way in its little over six-decade history. The museum was launched by industrialist Ralph Norton and his first wife, Elizabeth, who assembled a considerable collection of paintings and sculpture in Chicago. Many were bought from living artists whom the Nortons visited.

When they retired to West Palm Beach, they decided to share their trove with the public, building the Norton Gallery and School of Art that opened in 1941. The spare Art Deco structure was designed by Marion Syms Wyeth.

The collection then numbered 500 works; today there are more than ten times that figure in the Norton’s permanent holdings. Growth of the size of the collection and increases in the museum’s educational programs prompted the 1997 expansion and this year’s wing.

With its handsome new facilities and augmented gallery space, the Norton has become an even more significant Florida cultural attraction. As the opening exhibitions demonstrate, special shows and displays from the museum’s rich permanent collection will appeal to even the most sophisticated and experienced visitor.

On July 5, a summer exhibition will open, “An American Celebration: Recent Gifts to the Permanent Collection” that will feature works by Frederick Frieseke, Abbott Fuller Graves, Robert Henri, Rockwell Kent, Louis Ritman and John Sloan.

Available in the museum shop are catalogs with essays and color reproductions of major works from the Norton’s American collection (293 pages) and European collection (241 pages) available for $35 each, soft cover.

The Norton Museum of Art is at 1451 South Olive Avenue. For information, 561-832-5196 or visit www.norton.org.