As I surveyed display cases that form “James Lee Byars: The Art of Writing,” at the Museum of Modern Art, I couldn’t help but think how old-fashioned, how quaint, it all seemed. And it got me thinking how quaint the old MoMA used to be.

Quaint isn’t fashionable in 2007. Certainly Yoshio Taniguchi’s MoMA, whatever its virtues, lacks all quaintness. And maybe that’s why with this exhibition, we can sense the quaintness of the 1960s, the decade “The Art of Writing” covers.

The exhibition principally comprises numerous letters or missives that the artist Byars sent to the MoMA curator Dorothy C. Miller beginning in 1959. These and other small pieces by Byars take us up to 1977. (Byars died in 1997, at the age of 65.) In 1958, Byars, then an unknown artist, came to New York from Detroit with the intention of meeting Mark Rothko. Byars went to MoMA, apparently figuring someone there could put him in touch with Rothko. Perhaps not knowing what to do with Byars, the front desk summoned Miller. It’s evident that something in Byars moved Miller deeply, as we see in a 1961 recommendation letter she wrote on his behalf to the Guggenheim Foundation: Byars, she wrote, possesses “certain very sound ideas about simplicity and directness, both in art and in living.” (The writer and “cultural impresario” John Brockman, who was Byars’s close friend, wrote that “he kept only four books at a time in a box in his minimally furnished room, replacing books as he read them.”) More to the point, she arranged for Byars to exhibit his large works on paper in the museum’s emergency exit stairwell, in the very year he first showed up at MoMA. For a 27-year-old artist just arrived in New York from Detroit, that emergency exit stairwell must have seemed like heaven. And how quaint the story! When, one wonders, did MoMA last offer an exhibition to a young artist who just showed up at the front desk? When, indeed, did MoMA last summon a curator — as opposed to, say, a security guard or an intern — to greet such a visitor?

The small show’s hallmarks very much include the “simplicity and directness” noted by Miller, to which I’d add sweetness, a fine sense of order, and, of course, quaintness. Byars’s letters to Miller weren’t ordinary letters, typed on 8 1 /2 by 11 paper. Byars wrote his letters on shaped, textured, folded, or packaged paper. He often used different kinds and colors of tissue paper, and handmade Japanese paper. In one undated letter, Byars wrote in pencil on a long piece of pink tissue paper that he shaped like a snake and coiled inside a yellow satin pouch. Byars spent time in Japan, and the Japanese influence — folding, scrolling, packaging — seems to infuse everything he does with a serene and orderly Zen flavor. He had, if not a calligraphic hand, a very mannered script that he varied — in the size, spacing, and color of letters — for effect. This, combined with the care with which he handled the paper — bordering it, cutting it into circles or quarter ellipses, scrolling it — reminds us of a seemingly impossibly distant time when people not only routinely sent letters, but often, whether through carefully chosen stationery or the puff of perfume, rendered the letter not just a bearer of sentences but an evocative object in itself. Byars gave artistic expression to the posted letter’s objectness. A lost world rises up from these display cases.

Byars won renown in part as a performance artist. On October 10, 1964, he showed up — as he had five years previously — at MoMA’s front desk. At 10:00 a.m. he removed his hat, smashed it, and sent it up to Miller. All the letters are similarly “performative,” but in the end exist not in the significance of a timed gesture, but as lovingly crafted keepsakes. Byars affectingly used gold paint and gold leaf, often on black backgrounds, evoking black-and-gold marble. In one instance a Rothkoesque combination of gold and orange squares serves as a background to his handwriting on Chinese paper. In another instance, he wrote in high, compressed red letters on a scroll made from humble calculator tape. He also gloried in typefaces, the tinier the better, at a time when font-swapping hadn’t yet become a middle-American recreational pastime. Byars’s simplicity and directness didn’t reject technology, and Byars hung out with cyber-guru-types. The present exhibition, though, pulls up far short of anything Byars might have done with computers. The sweet and serene objectness of these letters reminds us that in some ways the putatively radical 1960s bore more in common with the age of Jane Austen than perhaps with our own.

Until October 29 (11 W. 53rd St., between Fifth and Sixth avenues, 212-708-9400).