At 9 am there was a line outside the door of Adam Lippes’s Fifth Avenue address. An Architectural Digest feature on the designer’s recent renovation of the space (with private living quarters and a salon for his business on opposite sides of the foyer) might’ve played a part, but Lippes’s clothes are plenty sumptuous on their own—quite possibly the richest and most luxurious New York has to offer. It’s hard to think of another brand based here in the city that puts such a premium on the finest materials—a handwoven silk with delicate slubs, a traditional plaid made in sheer and opaque organdy, silk embroidered with crystals in a motif lifted from the wallpaper from one of the grand houses of Newport, Rhode Island—with the possible exception of The Row.

Lippes originally launched his label in 2006, as a veteran of the Oscar de la Renta design studio, and he said the 20-year milestone gave him a reason to reconsider his first collection’s preppy bona fides. With Michael Rider ascendant at Celine and Ralph Lauren riding high again 60 years into his own historic run, American prep is the defining look of the moment. Lippes’s take on the sensibility is subtle, in keeping with his own proclivities. In fact, many of the pleasures of his clothes are reserved for their wearer’s own enjoyment, like the tan bomber in waterproof silk that unzips to reveal a tonal plaid. Boyfriend jackets in silk and linen Loro Piana tweed, meanwhile, look as good as they feel. Ditto the supplest of black leather jackets.

But it wasn’t all understated. Lippes had his fun, too, with a pair of red running shorts in silk taffeta, a garment that has gone from workout gear to club wear. Lippes’s landed somewhere in between. Paired with a blouson jacket, his customer might wear them for a shopping excursion on Madison, or for an errands run before tennis at the club somewhere upstate or at the beach. “Really,” he said, “the starting point was trying to update it all for today from where we’ve come from.”

Evening pieces strayed somewhat from the preppy script. In the mix were a net slip dress embellished with micro Swarovski crystals, a curvier dress with a godet skirt in black lace, and an evening jacket with a high neck that tied in a bow, worn with flowing white balloon pants. Displayed as they were on mannequins in Lippes’s living room with its wood paneled walls, marble fireplace, and Gilded Age porcelain chandelier, they formed a tableau: art de vivre in excelsis.