Sculpture: Plaster Cornucopia

If an artist is judged by the company his work keeps, Peter Agostini is a pop sculptor. At the current sculpture exhibition in Manhattan's Jewish Museum, Agostini's plaster popovers are on show across from George Segal's plaster mummies. All summer long, some of his clustered plaster balloons hung, like monster grapes for a superbacchanalia, outside the New York State Pavilion at the World's Fair next to Robert Indiana's EAT sign, Roy Lichtenstein's cartoon, and Jim Rosenquist's billboard.

But neither by temperament, background nor age does Agostini count himself among pop artists. At...