Discovering the Impressionists, now on view at the Philadelphia Museum of Art, tells the story of French art dealer Paul Durand-Ruel, who championed work by then-unknown painters Monet, Pissarro, Degas and Renoir. Purchases he made in the earliest days of Impressionism are on view along with later Impressionist works. Previously in Paris and London, this superb exhibition will not travel anywhere else in the United States.

Durand-Ruel first met Monet and Pissarro in London, where the Frenchmen had taken refuge to escape the Franco-Prussian War. He began buying their paintings and displayed them beside works by Millet and Corot in the London branch of his Paris-based gallery. After the war, he continued to support Impressionism, systematically buying canvases and renting his gallery for the second Impressionist Exhibition in 1876.

To build his business, the art dealer used innovative tactics that have since become commonplace. “His strategy was to get exclusivity for the artists’ works,” says Flavie Durand-Ruel Mouraux, who maintains her great-great-grandfather’s archives. “He staged the first solo exhibitions of a single artist’s works and presented international exhibitions in Europe and the United States. He used the media to promote the artists.”

By the end of his life, Durand-Ruel had purchased nearly 12,000 Impressionist works. He generally bought directly from artists, but also bought paintings at auctions, bidding up prices so that works would not be seen to lose value.

In exchange for a commitment to exhibit exclusively with his gallery, Durand-Ruel sometimes provided an allowance to his artists. A regular, reliable income enabled Monet, Pissarro, Renoir and Sisley to concentrate on painting and developing the new art form.

Durand-Ruel ran an international operation, with outposts in London, Brussels and New York. After his first exhibition in New York City in 1886, Americans began visiting Durand-Ruel’s Paris gallery. “Without America, I would have been lost, ruined, after having bought so many Monets and Renoirs,” he wrote. “The two exhibitions there in 1886 saved me…after that the French public followed suit.”

Perhaps not surprisingly, many of the more than 80 paintings shown here are familiar from past Impressionist exhibitions or museum visits in Paris, London and Philadelphia. But others, such as Degas’ mysterious “Peasant Girls Bathing in the Sea at Dusk,” 1869-75, and Monet’s “The Church at Varengeville, Morning,”1882, are privately owned and rarely on public display.

This exhibition also includes six door panels by Monet. Commissioned by Durand-Ruel, the paintings are displayed against enlarged photographs of his Paris apartment, the panels’ original home.

Among the 15 paintings by Renoir here are three large pictures of dancing couples. Two of them, “Dance in the Country,” 1883, and “Dance in the City,” 1883, hung together in the grand salon of Durand-Ruel’s apartment. The third picture, “Dance at Bougival,” 1883, depicts a couple dancing at an open-air cafe.

Of particular note is the reunion of six paintings from Monet’s 1891 series, “Poplars.” Of the 24 versions of this subject painted by the artist, fifteen were shown in the Durand-Ruel Gallery in 1892. Each is different in perspective, color and weather conditions, but all have a similar composition, showing the same stand of trees in a zigzag pattern.

Not part of the exhibition but on view in the museum’s Impressionist gallery is Pissarro’s “Railroad to Dieppe,” 1886. Although Durand-Ruel disapproved of Pissarro’s venture into pointillism, he nevertheless bought this radical canvas the year it was painted. The painting, almost abstract in its composition, is further proof of the support Durand-Ruel gave his artists and a complement to this excellent exhibit.

“Discovering the Impressionists,” on view through Sept. 13, 2015, Philadelphia Museum of Art, 2600 Benjamin Franklin Parkway, Philadelphia, PA, (215) 763-8100, www.philamuseum.org

More information is available about Ms. Saul’s work at www.artbookannex.com and www.pissarrosplaces.com.