Leon Polk Smith’s life sounds like the stuff of lore. Growing up in Oklahoma among Choctaw and Chickasaw Indians, Smith (1906-96) decided to pursue painting when he stumbled upon a college art class in his 20s. He moved in 1936 to New York City, where seeing Mondrian, Brancusi, and Arp changed his painting forever. Thereafter he pioneered a hard-edged painting style, infusing the elemental abstractions of Mondrian with a Westerner’s sense of wide, lyrical expanses.

It would be difficult for any paintings to live up to so promising a life story, but there is a single-minded intensity to the 20-odd works on paper at Jason McCoy commemorating the centennial of his birth. Dating mostly from the 1950s, they reflect a period when the artist had moved from the angular forms of Mondrian to simplified compositions of two curving elements.

An untitled mixed-media work from 1955 shows the traced outlines of two hands, with thumbs and forefingers barely touching to form a kind of private window onto indefinite depths. The only overtly representational work here, it could symbolize the search for “significant form” (to use the critic Clive Bell’s phrase) that animates every piece here.

One also senses this search in an untitled oil painting on paper from 1955, in which the dividing line between blue and white areas curls ponderously from an upper corner, then abruptly jackknifes down and back before set tling at the opposite edge. In an untitled gouache from 1958 that hangs in the gallery’s back room, a zigzagging diagonal probes and regulates a mass of competing green and white bars. Elsewhere, an untitled gouache and collage from the same year features a single white form on a black field; its upswept, curling edges suggest a slowly descending butterfly or leaf.

For all their taut austerity, such compositions have a gracious ease. They may not match the complex resonance of Arp’s designs – with his continuously quickening contours – but they dissect their spaces with confident, one-shot precision.

The installation, with its blue-gray walls and large frames trimmed in off-white and buff colors, strives to invoke the aura of Western spaces. The effect may be a little too obvious for some viewers, as these paintings speak for themselves, and with elegant authority.

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The paintings of Jay Milder (b. 1934), too, hint at an exotic early life. The son of a Chasidic mystic, Mr. Milder frequented the jazz clubs in his hometown of Omaha before leaving for Paris in the mid-1950s to study painting. With Red Grooms, Mr. Milder staged some of the very first “happenings,” and later collaborated with Jim Dine and Claes Oldenburg on other projects. In his own paintings, however, Mr. Milder always shunned the cool control and irony of Pop art for a more painterly, mystical approach.

With his recent work at Lohin Geduld, the artist continues to engage Old Testament subjects with evocative textures, glowing hues, and tumbling, abstracted forms. Titles like “In the Beginning” and “Kabbalah 15,” rather than pictorial details, illuminate the nature of his spiritual aspirations.

Mr. Milder’s colors jostle and pulse with the energy of a pinball machine. In the 6-foot-tall “Noah’s Arc 43” (2004), deep yellow and cadmium-red circles sweep through irregular shapes of dark pink and vivid yellowgreen. The artist’s shapes tend towards a single, smallish size, imparting an evenly developing, allover rhythm to his canvases. Apart from occasional portions of faces and animals, the only recognizable elements are numbers and letters swirling cryptically in the mix.

Viewed en masse, such repetitions of color and gesture can make the mysticism in these paintings seem a bit automatic. Several small drawings, however, show another order of spontaneity. “Ark 31” (2005), executed in oil pastel, watercolor, and ink, unfolds bit by delicious bit, as large, buoyant animal forms encounter smaller knotted forms and sporadic polka-dotted fields. Always notable for their idiosyncratic energy, here the artist’s ideas appear to flow as freely as his watercolor and ink.

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The achievement of the American artist Sandra Fisher (1947-94) was overshadowed during her lifetime by her husband R.B. Kitaj and other School of London artists. Now, 12 years after Fisher’s death from a cerebral hemorrhage, the New York Studio School’s exhibition of nearly 70 works by Fisher and her colleagues explores her role as an artist and muse within this lively circle. Curated by my New York Sun colleague David Cohen, this snugly hung exhibition honors Fisher’s preference for salonstyle installations.

Among the numerous portraits of Fisher is Mr. Kitaj’s beautiful and affectionate pencil and charcoal sketch from 1981. Other portraits include Frank Auerbach’s pastel and charcoal work from 1973-74 and Raphael Soyer’s 1983 double portrait in oils of the artist with her husband.

Fisher’s nearly 50 paintings and works on paper are conservatively impressionistic in style, but her subjects – especially her voyeuristic portraits of young nude men – suggest a free spirit. Her portrait “Susannah Drawing” (1983) vividly captures the intense stare and deeply shadowed features of an artist at work. Fisher’s drawing and brushstrokes remain vigorous throughout these works, but her palette less so: Lights and darks at times lose their colorfulness, and mid-toned hues tend toward the jarring. But this, perhaps, can be attributed to an independent temperament, one that was both traditional and youthful in outlook, and inspiring to many around her.

Smith until June 3 (41 E. 57th Street at Madison Avenue, 212-319-1996). Prices: $18,000-$35,000. Milder until May 20 (531 W. 25th Street, between Tenth and Eleventh Avenues, 212-675-2656). Prices: $1,500-$28,000. Fisher until May 13 (8 W. 8th Street, between Fifth and Sixth Avenues, 212-673-6466). Prices available on request.