In architecture, details matter. The principle was brought home for me during a visit to the recently completed Ara Pacis Museum on the banks of the Tiber River in Rome. Designed by the New York-based Richard Meier, the building itself exhibits many of the powerful spatial effects and much of that quadratic elegance that are the signature of the architect. The fountain in the plaza out front, however, is a complete disaster. The problem is not so much with the design as with the materials, the engineering, and the maintenance of the waterworks. In homage to the architectural traditions of the Eternal City, much of the plaza is clad in travertine, a porous, igneous stone, susceptible to infestation.

Only a year old, the entire wall of the foundation area is already covered in reddish-brown algae. Because this is just about the first thing you see as you enter the museum’s grounds, it casts a pall of ineffaceable abjection over the entire project. As you step closer to the fountain itself, its shallow pool marked by a sequence of liquid jets, you notice refuse and plastic bottles bobbing about in the fountain’s gutters or rutted in a pool of viscous fluid.

A better model for the handling of water in an architectural context is the Querini Stampalia museum in Venice, designed by Carlo Scarpa and the inspiration for a new book, “Strange Details” (MIT Press,176 pages, $19.95), by Michael Cadwell, an architect and professor at Ohio State University.

Scarpa, who died in 1966 at age 60, was a modernist who was nevertheless rooted in the artisanal traditions of his native Venice. Indeed, he even designed glassworks for the famed factories of Murano. In re-imagining the interior of the Querini Stampaglia palazzo, which dates to the 16th century, Scarpa made extensive use of Istrian marble — far harder and more resistant than travertine — to form the discreet runnels along the walls, through which the water is channeled. Since crowded contemporary Venice can not accommodate extensive new construction, Scarpa’s achievement, both in this museum and in his Olivetti flagship on the Piazza San Marco, consists of the incremental effect of countless tasteful details: Bauhaus-inspired tiles in the museum’s foyer, the patterns of inlaid stone on the floors of the gallery, and the concrete accents in the garden courtyard.

It was through such details as these that Mr. Cadwell “came to understand how Scarpa cast this spell: how he liquified materials and how, in doing so, he sometimes gave rise to an all-embracing spatial affect [sic] that unmoors us from the earth, leaving us to swim in a liquid ambiance.” In the course of his brief book, Mr. Cadwell provides admirably focused, legible, and sympathetic readings of the similar accomplishment of four very different structures, each in its way a milestone of mid-century modernist architecture. In addition to Scarpa’s museum, he discusses Frank Lloyd Wright’s Jacobs House, Mies van der Rohe’s Farnsworth House, and Louis Kahn’s Yale Center for British Art. The unifying theme among these works is a human sensitivity that implicitly or explicitly rejects the machine aesthetic that informed the intensely urban architecture of the International Style.

The history of architecture is in some sense the result of a tense engagement between the broad imperatives of function, structure, and massing, and the specific demands of detailing. In classical Greek architecture, once the innovative structural terms had been established, the glory consisted almost completely in the exquisiteness of detail: the Parthenon is a far nobler achievement than the Temple of Hera at Paestum, but no one would ever argue that the Parthenon was a whit more functional. In Gothic architecture, which excels in structure and detail, the latter does not emerge organically from the former, as in Classical architecture: Instead, both elements coexist in an odd marriage, where each maintains a certain independence.

For all its talk of rational design, 19th-century Beaux Arts architecture is defined by its prolific use of ornamental details, while modernist architecture, which once equated ornament with crime, is in most cases defined by what it excludes. In fact, the attention to detail that is evident in the four architects whose work Mr. Cadwell discusses is to some degree exceptional among modernists. It is not ornamental detailing, but structural detailing — such as Mies’s removal of any trace of bolts in the metal beams of Farnsworth House — or material detailing — such as Wright’s use of wooden beams in the Jacobs House.

Where do matters stand now, in the first decade of the new millenium? The neo-modernist architects Steven Holl, Jean Nouvel, and Renzo Piano, among others, have emerged out of modernism with a greater ability than their forebears usually had for leveraging meaning out of the felicitous invocation of details. At the same time, the escalating complexity of our built structures, arising from growing functional and ecological demands, are increasingly turning them into something closer to appliances than cultural artifacts. When their mechanical cores break down, as in the draining system of the Ara Pacis fountain, that lack of attention to detail produces an effect that is neither functionally nor aesthetically tolerable.

jgardner@nysun.com