‘Retrospective,” a group show at Gagosian’s 21st Street gallery, is like a summer concert festival with some very promising, big-name acts. Its organizing principle, the ways a major artist looks back and reassesses his — unfortunately, in this case, only his — career, also strikes a promising note. Too bad, then, that so many of these guys showed up out of shape, like Vegas has-beens listlessly running through medleys of their greatest hits.

For the opening act, Gagosian wheels out the granddaddy of most of today’s overripe rock-star artists, Marcel Duchamp, who, with his “Boîte en Valise” (1935-41), apparently invented the box set. His consists of a leather valise containing photographs, some hand-colored, and miniature reproductions of Duchamp’s best-known pieces. Yet one has to wonder about the intended audience: Can even those who revere Duchamp as the original aesthetic subversive appreciate a cheesy, shrunken “Fountain,” a photo of “Ready Made” (a wine-bottle drying rack) pasted on black construction paper like a scrapbook entry, and a repro of “LHOOQ,” his never-shocking, never-funny mustachioed “Mona Lisa”? It seemed to me less a greatest-hits collection than a sad, parodying self-portrait of an aging, artistically impotent man trying to make a buck off his past.

But one doesn’t have to look back very far to find artists making unintentional mockeries of themselves. Takashi Murakami (b. 1963) looks back as far as, like, yesterday. His “Superflat Museum” — here in both the “LA Edition” (2005) and the “Convenience Store Edition” (2003) — assembles 10 plastic figurines, miniatures of his sculptures or characters from his paintings. It’s the sort of thing you might buy from QVC during a drunken late night. And if you act now, for the low, low price of — insert absurd amount here — you get a 2-inch-high “Hiropon” (1997), handcrafted by the “renowned” toy manufacturer Kaiyodo, and complete with enormous lactating breasts. If you call in the next four minutes, we’ll throw in a certificate of authenticity, “a mini-portfolio including information about the work that inspired” the figurine, “as well as two pieces of chewing gum.” (All quotes taken verbatim from the press release.) Offer limited to two a customer.

To be fair, few of the other pieces here induce embarrassed giggles as easily as the Duchamp and the Murakami. Andy Warhol’s “Red” (1978), a silk-screen painting from his late — some might say Superlite — period, is a predictable mash-up of Warholian standards: a flower, a car crash, a cow, a Mao, a Marilyn, a Corn Flakes box, all in monochrome, except for the crimson flower. It’s not bad, just a glib design, something suited to a scarf — and by now, I’m sure, it graces one. Check a museum shop near you.

Still, mining the past for gold will sometimes turn up genuine nuggets. Although Richard Hamilton’s “Collected Words (Portfolio)” merely reproduces — again in a box set — nine collotype reproductions of studies for nine works, it does provide real insight into the trajectory of his career. It seems a more honest approach to autobiography than a mash-up or medley, and, in my opinion, the tentative and unfinished look of these sheets is more compelling, too.

Rather than present trinkets or postcards, à la Duchamp, the “Chris Burden Deluxe Photo Book” (1971-73) documents the artist’s early, seminal performances. Of course, such evidence constitutes the sole residue of those pieces and thus has an inherent value. And, though nothing more than humbly typewritten descriptions of the performances accompanying black-and-white photographs, the piece is strangely thrilling. Among the 13 images from “Shoot” (1971), in which Mr. Burden had an assistant shoot him with a rifle in the arm, is a frame in which the artist seems to flinch an instant before he is hit. Originally, the assistant was only supposed to graze his arm, but the bullet ended up piercing it. An image from “747” has grown only more shocking with age: It shows the artist on January 5, 1973, firing a pistol at a Boeing 747 as it’s flying over him.

A delta of detritus, sweepings from the artist’s studio — toys, a small plastic leg replete with sock and shoe, etc. — spill from an upended cardboard box in Tom Friedman’s “Inside Out” (1991-2006). It’s a simple piece, yet it provides an accurate portrait of the artist’s work in negative — those things that never made it into his installations.

Douglas Gordon, in “Pretty much every film and video work from about 1992 until now,” offers the only full retrospective here. Television monitors of different shapes, sizes, and vintages, each at a different height and depth, glow in a darkened room, painted black; on the monitors play more than 15 years’ worth of film works. The room makes for a stunning spectacle, and it has the advantage of allowing the visitor to enjoy all of Mr. Gordon’s work at once.

In the end, after seeing Mr. Gordon’s encyclopedia, Piotr Uklanski’s catalog of imagery, and Martin Kippenberger’s portfolio of 30 posters, one is left wondering if a female artist would do such a retrospective in a different voice. This show won’t tell us. It is nevertheless a mind-churning romp and, despite the instances of mercenary self-imitation, you’re likely to look back on it gratefully.

Until August 22 (522 W. 21st St., between Tenth and Eleventh avenues, 212-741-1717).