The new Institute of Contemporary Arts (ICA) on its harbour site in Boston combines, or fuses, several significant architectural themes. First there is the trope, initiated by Frank Lloyd Wright a century ago, of the exploded box, the parallelepiped of porous corners. Second is the modernist pursuit of the ultimate flexible container for exhibitions and art happenings, from universal spaces imagined by Mies van der Rohe to the kit-of-parts realised by Piano and Rogers at Beaubourg. Third is an evolving attention to landscape and ramped surface as witnessed at the Kunsthal, in Rotterdam, by Rem Koolhaas/OMA and the Villa VPRO, near Hilversum, by MVRDV. Fourth is the research carried out, over recent decades, by the ICA’s architects into architecture’s connection with the human body, specifically with regard to what might be termed the mechanics of observation or, even, the equipment of the voyeur. You see the building across extensive surface parking close to Downtown Boston. Its cubic form, wrapped in an upper band of vertical glass planks, is currently isolated between the massive Joseph Moakley Courthouse designed by Harry Cobb and a low-rise, vernacular restaurant. Most importantly it is perched right at the shoreline of Boston Harbour. Whereas the surrounding parking lots will in the future be developed as offices and apartments, the promenade along the harbour edge is already in place. Diller Scofidio + Renfro manipulate this timber boardwalk to carve deep into the ICA’s mass as, first, a set of grand public steps; then the floor, rear wall and ceiling of an internal auditorium; and, finally, the underside of a vast upper section of the building that projects with no visible support out towards the water. From this remarkable hovering soffit, a central patch of timber sheathing drops down to create a kind of upside-down dormer window. On a recent afternoon, the bulk of the building almost disappears against a dull maritime sky. The more observant visitor notices a translucent upper half sitting above a lower section faced in vertical panels of transparent glass and flush metal. Approaching the harbour, moving to the east or west, your understanding of the ICA’s form changes radically to an orthogonal upper volume hovering dramatically above a glazed foyer (with a colourful Chiho Aoshima mural) and the internal auditorium that, rising to a protruding linear bump along the south façade, continues the folded boardwalk surface. As night falls, the building turns into a glowing lantern. The entire upper section is lit from within to reveal a white wall with few clues to the interior—a mute billboard to the neighbourhood. The lower sections are illuminated to reveal the myriad contents and activities of the foyer and auditorium, both volumetric erosions from the general mass. These erosions suggest a dynamic upgrading of the exploded box to facilitate multiple points of entry and a sensibility tuned to material delicacy and acrobatic balance. The entryway is cut at a diagonal from the southwest corner, making for a slightly awkward lobby beneath the belly of the auditorium, a sloping surface incised with a constellation of narrow light fixtures. As the public boardwalk folds back overhead (it is also sliced open once to lessen its apparent weight and allow a short-cut in external circulation), the visitor proceeds inside the building to a ticket desk with suspended information screens, to a store slightly excavated from the lobby datum level, and a café that extends round the north façade to open out through floor-to-ceiling glass to the boardwalk and harbour views. You may then find yourself in a glass-sided elevator cab that ascends through the centre of the building as if in a sleek, technological canyon. Liz Diller and Ric Scofidio have long focussed on how bodies interact with machinery, a subject explored in sets for progressive theatre and dance companies, in the wonderful Brasserie restaurant (CCTV projections, translucent partitions, and a sense of voyeuristic drama) at the base of Mies’s Seagram Building on Park Avenue, and in their seminal retrospective exhibition at the Whitney Museum in 2003. Here in Boston, in an elevator ride offering glimpses in smooth succession of interior landings and water lapping in the bay outside, you may recall the architects’ characteristic concerns. The elevator is not as radical as that proposed by Koolhaas for MoMA in 1997, skewering the institution at an incline. At the ICA, the visitor doesn’t get to see inside the storage or service areas. It’s in that sense fairly orthodox. The canyon is kept compact, hosting also an elongated staircase with perforated metal sides and an ultra-slim, vertical light fixture. If these features are slightly fetishistic, the upper level is a cooler experience. You are now inside the large, topmost box wrapped in glass panels. Yet the interior doesn’t connect out to that glass membrane. These temporary and permanent exhibition galleries consist of a polished concrete floor and uniform white walls topped by a translucent plane of flush rectilinear panels. Here we might remember those early 20th-century spatial proposals for luminous, flexible space. Structure is kept out-of-view. The great cantilever, so communicative on the exterior, is subsumed internally to give priority to art and to the interior promenade between galleries beneath the contiguous, illuminated ceiling. If the glass-walled auditorium permits performance and film to occur in full view of the harbour, the galleries focus on hosting art objects (the inaugural show, Super Vision, appropriately attends to multiple issues of perception and visual technology). From afar, observation of the exterior reveals a central band of rooftop services and an array of small, north-facing skylights that filter natural light to the interiors. Visually these are minor or remote elements compared to the bravura moves of the folded boardwalk sheltering key public spaces and supporting, as if by magic, the great box of galleries. You should look for the protrusion seen earlier slanting from this electric iceberg. Embedded within the gallery sequence and accessed from two sides, it’s a stepped chamber fitted with grey banquettes and individual monitors like an aesthetically rarefied Mission Control. Here visitors surf the ICA web for in-depth information on exhibitions, artists and events. The slightly vertiginous space tilts to a singular mullion-less window directing your view down to a rectangular swatch of Boston Harbour. It’s not exactly subtle, this climax to an extraordinary box-of-tricks.