When he was asked to turn an empty room into a warm and welcoming library, David Mitchell started—not surprisingly—with floor-to-ceiling built-in bookshelves. And not just any bookshelves: These waxed white-oak shelves are bordered by inset strips of chocolate brown leather with French brass nail heads. The result is both sophisticated and inviting—and leaves plenty of space for the owners’ collection of more than 3,000 books.“This is a real reading library,” Mitchell observes. “It made it great that these books are really in use.” Sconces are attached to the leather strips and easels drop down from ceiling height to display a series of Art Deco gouaches. “They create a layered effect,” says Mitchell. “And they hide any books you don’t want people to see!”The designer combined traditional and modern elements. An antique rug is paired with transitional upholstered pieces from Donghia, including a subtly striped blue sofa and chairs and armchairs in an olive and ivory botanical print that brings nature in. In the window, a stacked box table by Ted Boerner provides a focal point; on it, accessories include a trio of pots purchased at the Smithsonian Craft Show and two dark-wood steering wheels from Model T Fords found by Mitchell at a salvage shop and mounted on stands. A coffee table by Baker is paired with the sofa, while Tucker Robbins’s barrel-shaped Spider’s Nest side table sits between the blue chairs. Silk fabrics from Donghia were cut and sewn in wide stripes to create drapes. The chandelier of wrought iron and parchment was designed by Paul Ferrante.

INTERIOR DESIGN: DAVID H. MITCHELL, David Mitchell Interior Design, Washington, DC. PHOTOGRAPHY: ERIK JOHNSON.DAVID MITCHELL'S TRADE SECRETS: