“As far as I can judge from reproduction, Kitaj finished on a high.” So writes Frank Auerbach, who lives in London, in the catalog accompanying the exhibition of final works by his friend and fellow painter, the late R.B. Kitaj. Visitors to the Marlborough Gallery have every reason to concur.

Kitaj’s “little pictures” from his last years in Los Angeles, to which he retired after 40 years in London, and where he died by his own hand last year, are more than an encapsulation of his art and his literary and cultural obsessions. This is a show of glistening gems, nuggets of querulous vitality that brim with curiosity and devotion. A whiff of valediction notwithstanding, it feels more like the artist was on the threshold of something exciting and new than that he was taking stock of his achievement.

These are little pictures with big ideas. Their scale should not be mistaken for a belated lapse into modesty. Kitaj’s hallmarks were bravura, bombast, and buffoonery. He was a history painter who took on such themes as modernity, alienation, nostalgia, war, struggle, and identity, whether sexual, spiritual, or ethnic. The way he painted always reflected in formal terms the emotional and historic complexity of his theme. His art would collide elements of art history, politics, and autobiography that audiences had grown comfortable compartmentalizing.

Many of these paintings are portraits of luminaries of modern thought. Kitaj was an inveterate networker, among both the living and the dead. In a thoughtful twist, the show opens with a set of small portraits from the 1960s of poet friends. These are oil studies, whether from life or photographs, that served as the source for a series of lithographs of, among others, Robert Creeley, Hugh MacDiarmid, and W.H. Auden. The oil is ingeniously smudged to intimate a sense of photographic emulsion, generating ambiguity about the poets’ proximity to the painter, as the snapshot element equally suggests presence and remoteness.

The late paintings are almost entirely of absentees. These include people he knew but lost, such as his estranged biological father captured in a poignant image of a troubled-seeming man leading a horse, or his young wife, Sandra Fisher, whose sudden death in London in 1994 precipitated his return to America. The majority of portraits, however, are of cultural heroes in a modernist hall of fame of his own construction. This personal pantheon includes the likes of Gershom Scholem, Marcel Proust, Ludwig Wittgenstein, Sigmund Freud, Spinoza, and an imaginary portrait, “Author of the Zohar” (2006). The scale and the odd mix of personal style and historic reference recall Byzantine icons — they are at once hieratic and devotional. There are also many self-portraits, often self-mocking in their pathos.

There is a hint of projective identification in his portraits of artists such as Max Liebermann, a scintillatingly tight, compact painting of 2007. But some of the richest works in the show are not portraits of people as much as of their artistic product. For Kitaj, it seems, commentary and reworking was a form of portraiture as much as it was the other way around. Some nudes acknowledge the British painter David Bomberg, for instance, who turned away from the early 20th-century avant-garde in Britain to pursue, with curmudgeonly independence, a personal expressionism.

“Rothko Island” (2006) shows Kitaj exiting the art scene with a wry smile. It is at once humorous and reverential in the way it celebrates but also sends up abstraction, using Rothko-like, pared-down lozenges of color to represent landscape. He also pays homage to gentile patriarchs of modernism such as Paul Cézanne and Edvard Munch in ways that connect with his secular, provocative notion of himself as a “Diasporist,” the name he gave his one-man movement of Jewish painting.

“Jewish Scream” (2007) acknowledges Munch with a macabre humor that is itself, so to speak, a scream. “Jewish Bathers” (2007) contemplates a nude of ambivalent gender whose posture is somewhere between Cézanne’s youth with outstretched arms and a crucifixion. The rough, dark lines of oil on exposed canvas — at once robust and tremulous — puts the viewer in mind of Cézanne’s draftsmanship, but then in almost belligerent isolation from the drawing are smudges of color. As if a commentary on what is underneath, these “little sensations” complicate as much as they clarify the drawn element.

In many ways, the glory of these late little pictures is that they vindicate Kitaj’s controversial turn in the early 1990s toward a fast, perfunctory, scribbly, linear expressionism that departed from the relatively tight, controlled, considered expressionism that preceded it, and even more so from his meticulously composed, almost graphic-design-like early style. These last paintings manage to fuse the awkwardness of his late style with the formal rigor of earlier ones. Individually, they are not the big, ambitious pictorial machines that will always define his career. Collectively, however, this last creative spurt can be taken as an extended, multifaceted self-portrait.

Seeing these paintings framed and hung in sequence around the gallery has the twin effect of making one realize their individual painterly resonance and helping one construct a personal narrative, a sense of authorial presence. But documentary photographs such as the one on the catalog cover recall a different and suggestive earlier use of these images in the artist’s studio. Unframed and stacked, to be flipped through casually, they evoke index cards, cataloging the artist’s range of reference.

This also makes sense of the rough, notational, sketchy nature of Kitaj’s late hand. The frenetic, provisional feel to the paintings, which in some ways are more like colored drawings than paintings per se, seems calculated to remind artist and viewer alike that the image is not an end in itself but a marker of bigger intellectual possibilities ever beyond the frame.

And yet, in contradiction to this way of reading his work, these are rich, resolved, rewarding pieces of art, possibly among the artist’s best. David Hockney, also writing in the catalog, understands the essence of this contradiction when he describes Kitaj as “a unique, marvelous artist who thought content more important than form, yet knew they were one.”

Until May 3 (40 W. 57th St. between Fifth and Sixth avenues, 212-541-4900).