Like some otherworldly master of ceremonies, the American artist Joseph Cornell (1903–72) leads us from dream to childhood to religious ritual all within a single “box” or collage. Everything Cornell touched — tiny toys, broken mirrors, colored sand, yellowed newsprint — is transformed. And every Cornell rectangle resists its incarnation as frame or container to become cage or wound or premonition, or to become a window or a portal into another realm.

Originally influenced by the Surrealist collages of Max Ernst, Cornell began making two-dimensional collages in the early 1930s (and, later, the three-dimensional “boxes” for which he is so well known), a unique vocation he pursued until the end of his prolific life. Yet Cornell, unlike Ernst, whose collages were grounded in the Surrealist bent on creating shocking and rebellious juxtapositions, was a poet and a diviner. He focused not on weirdness but on pictorial and poetic cohesion — a cohesion that, surfacing like a long-forgotten memory, materializes as much in the heart as in the mind.

Approximately 50 of Cornell’s beautiful constructions and collages (what he referred to as “poetic theaters”) are on view in the exhibition “Andromeda Hotel: The Art of Joseph Cornell” at the Katonah Museum of Art. Curated by Therese Lichtenstein, “Andromeda Hotel” is a compact grouping of artworks, many of which, rarely seen by the public, are named after French hotels or constellations. A complementary show, “Case Studies: Art in a Valise,” curated by Suzanne Ramljak, occupies an adjacent gallery at the museum. “Case Studies” is an exhibition of suitcasebased works centered on Cornell’s “The Crystal Cage (Portrait of Bernice)” (c. 1934–67) and Marcel Duchamp’s “Boît-en-Valise” (1952), one of a series of works Cornell helped Duchamp to assemble.

One of the first works on view in “Andromeda Hotel” is a photographic portrait of Cornell by Lee Miller. The gelatin silver print shows the artist’s head in three-quarter view and as if lit from within, floating in the darkness. A large toy sailboat hangs from his head like wings or the headdress of an Egyptian pharaoh. A butterfly is perched on his temple, and a long lock of hair cascades from his head down the ship’s main sail.

Miller’s “traveling” portrait of Cornell seems to have set the metaphoric tone of the exhibition. Travel, the hotel, navigation, birds, games, windows, storage, and constellations are the themes of the works in the show.

Cornell can evoke any number of moods. Seen against the blue walls, some of the seemingly worn and weathered, predominantly white works, such as “Columbier” (n.d.), “Grand Hotel — Hotel Taglioni” (1954), and “Untitled (Hotel de l’Etoile)” (c. 1958), have the aura of classical costal ruins set against the Aegean.

“Little Mysteries of the Ballet” (1941), a tiny magical assemblage, mostly in pink — of a pink rose, dazzling fairy dust, sea shells, wire, and white tulle that drifts like a cloud, all in a glass-covered black box — is, exactly as its title suggests, the quintessence of the “Nutcracker.” The box construction “Untitled (Dovecote)” (late 1940s), painted a light blue, appears to open into the darker blue walls. A board punctuated with a grid of 20 circular holes, some of which are sealed, some of which are open, and some of which hold balls, “Dovecote” embodies loneliness, loss, mystery, and interiority; a ghostly carnival game, a home for pigeons, and a monastery.

In the photo collage “Untitled” (n.d.), the bust of a female saint dressed in red emerges from out of a stormy, red-violet sky. The saint, as if she was born of a union between the trees and the heavens, is at the center of the collage, and her robes spread across the image like curtains or a ground plane. Two groups of trees, one rising upward, and the other moving downward, grow out of her robes. Filled with light and startlingly sanguine, the image, like an icon, is both promising and foreboding.

Cornell achieves a universal sense of longing in his art. Filled with things — some natural and some manmade, some recognizable and some not, some broken and seemingly lost, others found — he creates a theater of transitions where, as in dreams and poetry, everything is itself and yet so much more. Cornell makes use of specific references (Renaissance artworks, Victorian toys and ephemera, animals and maps, as well as famous film stars and ballerinas); but his art transcends its meager beginnings and moves into the world of fantasy, memory, and make-believe.

What sets Cornell apart from his many followers — his contemporaries Duchamp, Robert Rauschenberg, Jasper Johns — is his unique ability to honor, celebrate, and then to transform the commonplace. In Cornell’s hands, a child’s pock-marked rubber ball becomes the sun, the moon, a human head, and the epitome of play — yet it never loses its identity as a worn rubber ball. It remains neutral: it is every child’s ball and my childhood ball.

The 30 works from the last 70 years in the show “Case Studies: Art in a Valise” make clear why Cornell is a master who stands above his imitators. The small exhibition is thematically clever and catchy, as well as surprisingly varied and thorough. It includes suitcase art by Joseph Beuys (“I Know No Weekend” [1971–72], a black suitcase occupied by Kant’s “Critique of Pure Reason” and a bottle of seasoning sauce); Tony Oursler (“Anvil” [1997], a suitcase containing a video projection of a talking woman on a doll’s head); Marshal Davis (“Travel” [1994], a suitcase with two wheels), and Yoan Capote (“Nostalgia” [2004], a suitcase filled with bricks).

Ultimately, though, “Case Studies,” whose catalog is shaped like a suitcase and whose essay is titled “Unpacking Suitcase Art,” is a cliché filled with clichés. In terms of art, the show (although it includes a work by Cornell) has absolutely nothing to do with the magic of the master. Focusing our attention on the “case” rather than on what’s inside, “Case Studies,” which suggests that anything in a box is worthy of our attention, diminishes Cornell’s mystery.The exhibition does what it does well: It gives us a range of suitcase art, some of which will generate perplexity and smiles. But the question remains: Was any of it worth unpacking in the first place?

Until September 17 (Route 22 at Jay Street, Katonah, N.Y., 914-232-9555).