"You know, Mona is launching activewear this season," deadpanned Assembly New York owner Greg Armas at the start of today's A Détacher show. "Activewear for reading." Armas—a devotee of A Détacher—was joking. But "activewear for girls who read" wouldn't be a bad way of describing Mona Kowalska's clothes. A slinky sweater dress, for example, somewhat sheer around the collarbone and banded at the bottom, is just the kind of chic, easy piece that works perfectly well for an art opening, a matinee at the Film Forum, dinner at the Waverly, or an evening cozied up on the sofa with Lydia Davis' new translation of Madame Bovary. Ditto a silk jumpsuit in a graphic purple and white squiggle print, or an extra-long, grass green cashmere cardigan.

There was a particularly academic, tweedy feel to A Détacher this season, never mind the absence of any actual tweed. Wide-wale corduroy jackets and dirndl skirts came off boho-preppy, while sweaters with knit-in ruffle details and long shift dresses were winningly gamine. Some of the strongest looks here were the most pared-back, notably a collarless blouse and high-waist trouser combo in contrasting shades of gray wool, topped by a surprisingly understated purple fur vest. Again: easy, chic. Kowalska also impressed with this season's accessories: A nubby knit, used in vests and long scarves, also featured in the must-have headband/kerchief hats worn by all the models, and a simple white clutch bag was minimally perfect. All in all, it was another collection of exceptionally smart clothes that are no-brainers to wear—and therefore leave plenty of mental space free for thinking about other things.