An Alice Neel painting pops against Knoll Ultrasuede, which swathes the library of an art-collecting couple’s Park Avenue apartment, designed by David Ries and Thad Hayes, partners in the firm Ries|Hayes. The custom-made sectional sofa is upholstered in a Cowtan & Tout fabric.

Ries and Hayes installed hand-painted folding doors along the entrance hall, where visitors are greeted by a Fernand Léger canvas and an Alexander Calder mobile.

In the living room’s main seating area, 1960s lounge chairs designed by Illum Wikkelsø for Holger Christiansen join a cocktail table and sofas by Ries|Hayes. A Henry Moore bronze perches on a pedestal next to a Paul László tiered console featuring reverse-painted tiles by Karin van Leyden, while a Bruce Nauman sculpture stands in the corner near a midcentury French armchair in the style of Jean Pascaud from Maison Gerard.

An Émile Othon Friesz landscape painting adds a splash of color against the living room’s wall, which is covered in Loro Piana wallpaper; the floor lamp is a 1960s Italian design, and the walnut side table is Danish from the 1930s or ’40s.

At the living area’s other end, Ries and Hayes designed a multipurpose table in the same stone and steel as the room’s cocktail table, as well as cane-back chairs with Edelman leather seats. The painting is by Helen Frankenthaler, and the cast-iron sculpture by the window is by Tony Cragg.

In the bedroom’s vestibule, a Ries|Hayes ottoman is positioned beneath a
work by Willem de Kooning.

A large Jean Dubuffet artwork presides over the primary bedroom, whose walls are lined in a Gracie silk. Ries and Hayes designed a frame for a 1960s Paul Evans screen to create a divider next to the custom-made bed, which features a headboard covered in a Fishman’s Fabrics leather, Matouk bedding, and a Loro Piana cashmere throw. The bedside opal glass pendants are attributed to Angelo Lelli, and the chair is by Elan Atelier.