You’ve got to hand it to Larry Gagosian. Any museum would envy "Claude Monet: Late Work," the exhibition of 27 paintings from Giverny by Claude Monet. Sweetened with loans from private collectors and distant museums (among them the Marmottan in Paris, Beyler in Switzerland, the Kitakyushi Municipal Museum in Japan and The Chicago Art Institute), the show is a one-time opportunity. And while our American museums would demand a hefty admission fee for such a survey, at the gallery it is free to the public. No wonder the line stretches down the block.

Monet’s magnificent paintings, made between 1904 and 1922, are the products of a mature genius. The celebrated dean of Impressionism was 64 when he began using his garden, lily pond and Japanese bridge as major subjects of his work. Rich and successful, Monet had cultivated his public persona as carefully as he cultivated his magnificent garden, while keeping his private life strictly under wraps. As Monet scholar Paul Hayes Tucker points out in the show’s catalogue essay, Monet was no bohemian.

He enjoyed fine clothes, foreign travel, great wines and driving in his fast automobile. His Giverny household employed a butler, a cook, a covey of maids and six gardeners, who used clay pots to position the water lilies in the shallow pond in summer, while bringing them indoors for the winter. And though he might begin a painting en plein air, Monet almost always finished up inside. His monumental late works were executed exclusively in the studio, as he often used easels on wheels to maneuver his increasingly huge canvases.  

The Gagosian exhibition divides into two parts that reflect a major division in the artist’s personal life and the cataclysm of World War I. The first gallery contains eight of the Nymphéas Monet painted between 1900 and 1909. In these pictures Monet has vanquished the horizon line and lowered the vantage point. Each is a study grounded in observing nature that abstracts the changing colors and aspects of the light and times of day. Delicate yet broadly rendered, asymmetrical arrangements of lily pads and flowers punctuate the shimmering surfaces of the water and the reflections of the sky’s changing colors.

The centers of these pre-1909 compositions are often empty, with circular groups of lily pads pushed to the sides or to the paintings’ edges. Monet’s assured arsenal of brushstrokes range from the most delicate whiplashes to broad, audacious slashes of color. The colors -- light and deep blues, blush pinks, purples, all manner of greens, pale yellows and whites -- are simultaneously pellucid and engulfing.

"Never in all the years since mankind has existed and men have painted has anyone painted better or quite like this," wrote critic Roger Marx in 1909, after he had visited "Nymphéas: Séries paysages de l’eau," the exhibition of these paintings at Durand-Ruel that Monet himself had supervised. None of the paintings were actually sold at the time (Durand-Ruel himself eventually would buy 15 of them in 1911). But critics quickly recognized that with this show the old artist had reclaimed his position as a leader of the French avant-garde. And this at the very moment when Picasso and Braque were busy inventing Cubism and Matisse and Derain were still gaining Fauvist notoriety for their strident palettes and uninhibited brushwork.

Still, these pre-war paintings are relatively tame, fussily framed in gilded ormolu, and could easily have embellished any Parisian or Park Avenue drawing room. Only one of them, the 1907 Nymphéas, borrowed from the Musée Marmottan, with its vertical format, its pulsating reflections of a brilliant orange sunset and its radically empty foreground, gives a hint of what is to come.

Monet’s amazing post-1916 canvases fill the succeeding three Gagosian galleries. For between May 1911 when his adored wife died of leukemia, and 1913, when his son Jean died, Monet hardly picked up a brush. (He had previously also developed headaches and troublesome cataracts that reduced his ability to perceive color. His eye for color was restored and even intensified when he finally underwent a cataract operation on his right eye in 1923.)

In the spring of 1913 Monet embarked on his last great project. It was the monumental series of water lily murals that became his gift to the French nation. From 1914, throughout the war and until his death in 1926, the now-venerable painter created them, as well as many related studies and other paintings of Giverny.

In these late symphonic pictures, so radical for their time, we see that nature is destabilized and almost subsumed in fierce, lyrical abstraction. Monet increasingly favored vertical (portrait) formats, not conventionally used for landscapes, to maximize compelling visual drama, as he transformed water and air into cascades of color. In one late (1918-19), very dark painting, the branches of the artist’s beloved weeping willow tree twist and writhe into violent, snaky colored lines. In others, the lily pond is simply the basis for paintings organized with distinctive patterns and bands of reflected light and a series of luminous nocturnes drenched in unforgettable blue. The Japanese bridge and the path beneath the famous rose arbors become pretexts for abstract riots of shadow, scumbled line and iridescent color. Often Monet did not paint all the way to the edges of these increasingly large canvases, making viewers still wonder if the work is unfinished or simply remarkably free. His brushstrokes and textures are very quick and loose but completely under control.

Appreciation turns to awe with the final paintings made between 1918 and 1922. Almost 100 years after they were painted their utter confidence and intensity triumph over most recent abstract art. Monet kept these works in his studio and never exhibited. Most of these dazzlingly radical paintings in fact remained there for decades after he died and did not see the public light of day until the 1950s. (Until now they have not been exhibited in America since a 1978 exhibition at the Metropolitan Museum of Art). He promised the great murals that occupied his final years to the nation in 1918 but they were not finished until a year or so before he died and they were not installed in the Orangerie until 1927, a few months after his death.

"Claude Monet: Late Works," May 1-June 26, 2010, at the Gagosian Gallery, 522 West 21 Street, New York, N.Y. 10011

ALEXANDRA ANDERSON-SPIVY is a critic and writer who lives and works in New York.