From Pollock’s free-form loops to Kline’s slashes and Rothko’s vibrant, pooling hues, Abstract Expressionism was a remarkably diverse movement. All of its attacks shared, however, one essential trait: A rawness of means, expressed as uncompromising gestures or primal, irreducible forms and colors.

Two related exhibitions at the Neuberger Museum tell the intriguing story of the lesser-known gestural abstractionist Cleve Gray (1918–2004). Although sympathetic to the Abstract Expressionists, he had little appetite for their raw demonstrativeness. Nor did his penchant for mysterious, allusive images strictly fit the more clinical investigations of the Color Field painters who came on their heels. Chronologically and temperamentally, Gray was caught between the two camps.

The first installation features his most monumental work, the 28 20-foot-tall panels of “Threnody,” which the museum commissioned for its 1974 inauguration, and has periodically re-installed every few years since. The second, “Man and Nature,” curated by critic and art historian Karen Wilkin, includes 30 paintings produced by the artist over the three following decades. These pursue a series of styles based on large, reductive, calligraphic marks, brushed vigorously over backgrounds of subtly modulated colors. Through a steady evolution of forms, they reflect a remarkably consistent sensibility: An assiduous, philosophical probing, expressed in brisk yet delicate gestures suggestive of traditional Japanese and Chinese painting.

Indeed, the exhibition catalogue essays by Ms. Wilkin and the artist’s wife, Francine du Plessix Gray, describe a worldly man who wrote his thesis at Princeton University on Yuan Dynasty landscape painting, and — at a time when many of his peers sought to expunge every influence of the School of Paris — studied in France with André Lhote and Jacques Villon. Back in America, he edited books on David Smith and John Marin, and served as a contributing editor for Art in America.

And, he painted, tirelessly. In the chronologically arranged “Man and Nature,” his textures — evocatively brushy lines, the humming feathered depths of color — allude subtly and beguilingly to realworld events without resorting to actual description. “Conjugation #1 (The Egg)” from 1975, conjures a sensation of transparent containment, with black lines loosely circling on a pulsating white field. In the exceptionally handsome “Conjunction #151” (1976), brusque strokes curl inward on themselves, remassing as a dense dark at the bottom of a red plane. Scumbled over darker hues, the red gleams with an almost coppery luster between margins of rich green on either side. On the other hand, “Death of the Eagle” (1977) succumbs to a sentimental literalism Gray usually avoids; the provocatively splattered, winglike forms invite a response more appropriate to a Rorschach inkblot test. A painting from the “Ramses” series of the late ’70s packs zigzagging strokes — red over blue over green — in the lower corner of a canvas, elasticizing the surrounding plane of vibrant orange. Another muscular work, “Man and Nature #1” (1980), elegantly sections a white ground into irregular zones with thin, ranging black lines.

Hampered by arthritis in his final years, the artist used oil sticks to create designs, often brilliantly colored, with loose, stringlike lines flowing and knotting in suggestive configurations. “Dispersal of the Square #9” (2003) neatly sums up his philosophical attack; here, textural effects and compositional gambits inform each other, so that the elements of a square, sequentially tipping, emit trails of intense color.

The power of these paintings lies in their mining of our collective visual associations, captured in poignant gestures and textures. “Ab-Ex” die-hards may lament his lack of interest in the canvas-wide, hierarchical divisions of a Kline or a de Kooning. His invocations of the transcendent can, in fact, have an illustrational aspect. The whiplash impression of a ribbon of bright blue-green kinking horizontally across “Considering All Possible Worlds #15” (1991), for instance, calls to mind an electrical arc or wildly spurting fluid, but Gray signals its drama with textures rather than with a measuring of intervals. The earliest works, a group of 16 small studies for “Threnody” completed around 1972, are especially lax in formal terms; here, groups of equivocally vertical shapes seem to hope for higher meaning.

The finished “Threnody,” covering all four walls of a huge, darkened gallery preceding “Man and Nature,” has the vigor of a majestic saga. Great verticals and diagonals, their darkly colorful shapes possessing the weight of human figures — though not the specific attributes — stretch and bend palpably in space, their extensions anchored by occasional notes of brighter hues. Conceived as a tribute to the dead from both sides of the Vietnam War, the work’s drama is a factor of its immense size and the darkened environment, but no less so of the artist’s struggle to control and animate its grand expanses. Challenged physically by the vast surfaces, the artist responded in kind, with epic effect.

“Man and Nature” until September 2, “Threnody” until September 9 (SUNY Purchase, 735 Anderson Hill Road, Purchase, N.Y., 914-251-6100).