Into the center of a superheated art market comes “Masterworks of Six Centuries.” Organized by a half-dozen Upper East Side galleries, the annual show, which opens to the public this year on Thursday, arrives at a time when galleries are selling more and more art at art fairs than at their brick-and-mortar spaces.

“Six Centuries” was organized to reverse that trend. “People just don’t come into the galleries as much as they used to,” the director of the New York branch of the Didier Aaron gallery, Alan Salz, said. Mr. Salz cited the presence of fairs such as the International Fine Art Fair, which opens a day after “Six Centuries” in the nearby Seventh Regiment Armory, on Park Avenue, as one of the reasons for the show.

“For years it has troubled me — ‘saddened’ is probably a better word — that we can sit in the front of the gallery and watch as people walk by our window going to the Armory,” he said. “What I decided to do was to organize a little group of us within a few blocks. Let’s keep it simple. Let’s try to get people back into the galleries.”

Stretching for three blocks along Madison Avenue between 66th and 69th streets, “Six Centuries” is an art walk with each gallery presenting a themed show. Less a cohesive survey than selections from a collector’s cabinet, “Six Centuries” ranges from the Northern Renaissance to 19th-century England, demure nudes to pastoral landscapes, all within a quick stroll of each other.

Didier Aaron is showing the work of French painter Hubert Robert (1733-1808). A contemporary of Fragonard, with whom he traveled in Italy, Robert falls somewhere between Rococo and Neoclassicism. Forty of the artist’s drawing and paintings are included in the gallery, among them the painter’s “Pont Sur Une Rivière” (1798), Robert’s picturesque view of a river crossing.

There is a smattering of Dutch genre paintings at Lawrence Steigrad Fine Arts, along with English Restoration portraits and devotional scenes. The show, titled “The Exalted and Forgotten in Portraiture and Genre,” has a few surprises. Chief among them is a portrait of Oliver Cromwell painted by the 19th-century American artist Martin Johnson Heade (1819-1904). As painted by Heade, the Lord Protector is all shrewd-eyed and tight-lipped intensity.

The director of Lawrence Steigrad, Alexa Davidson Suskin, said “Six Centuries” was good exposure for the gallery, which occupies several rooms on the first floor of a townhouse on 69th Street. Of the 250 visitors who attended the opening night last year, half were new to the gallery, Ms. Suskin estimated.

Contemporary art is represented on 66th Street. Dickinson’s show, “Devotio Moderno,” presents the work of artist Joe Coleman alongside works of the Northern Renaissance. The effect is less jarring than one might imagine. If anything, Coleman’s dense and detailed works, crowded with political effigies and tattoo-parlor imagery, are foils to the earlier works. Among these is “Christ in Limbo” (c. 1450-1516), a hallucinatory image of purgatory attributed to a follower of Hieronymus Bosch.

In the same building, David Tunick is showing “Crossroads: Dürer to Warhol,” a prints survey show that follows the gallery’s reputation for eye-opening pairings of old and modern masters. Where else, one wonders, would Andy Warhol’s “Marilyn” share a gallery with Dürer’s 1498 woodcut “The Four Horsemen of the Apocalypse”?

A genteel air pervades “Georgian England: British Art, 1714-1930” at Richard L. Feigen & Co. on 69th Street. It’s not merely traceable to Sir Joshua Reynolds’s resplendent portrait of Richard Crofts (1775), seen in a red coat and breeches, assured of his place in the world. As the owner of the gallery, Richard Feigen, explained: “The idea behind the show is that the Georgian period is really one of the most, I would say, neglected periods, at least by the market.”

“The theory always seemed to be that the French are the fantasists and the British are rational. It’s really the other way around,” Mr. Feigen said, in reference to the 17th-century landscape painter Richard Wilson (1713-82), whose “On Hounslow Heath” (c. 1770) is also in the show. “Heath” is a delight: a view of the English landscape whose trembling looseness of brush seems the starting point for the later achievements of British landscape painting, particularly Turner and Constable.

James Graham & Sons, one of New York’s oldest galleries, is participating in “Six Centuries” for the first time this year, having recently moved to 67th Street. The gallery is showing the work of American painter Walter Gay (1856-1937), whose feather-brush paintings of interiors are filled with the kind of decorative art objects — Louis XIV tables, striped wallpaper, and Chinese porcelain — that were favored by the artist’s circle in Paris, among them Edith Wharton and Henry James.

One of the two directors of James Graham & Sons, Priscilla Caldwell, said an artist like Gay appeals to a very specific kind of collector, one she hoped would attend “Six Centuries.” “For the kinds of things we sell, I don’t have people coming in off the street to buy things,” she said. Ms. Caldwell said that her gallery did an increasing amount of business at art fairs and did not regret the decline in the number of gallery “walk-ins.” “In a way, it’s better for us. Everyone who comes up to see us is there for a reason,” she explained. “I sometimes think — I’ll be very unpopular for saying this — that foot traffic can be a bit of a waste of time.”