Ralph Rucci will never be a trendsetter. He sets himself apart from all that nonsense to focus on—some might say obsess over—more serious matters like fabric and construction, adopting an intellectual approach that can sometimes get ponderous.

But the designer has been lightening up of late, and his fall collection proved that brainy and pretty can happily coexist. Using cashmeres, wools, and silks in muted colors—gray, taupe, dark green, violet, and black—Rucci cut slim pants, close-fitted skirts, and easy jersey dresses that are bound to please his discerning clientele. He also showed plenty of his boxy, swingy jackets, the construction of which recalls those other thinker-designers Geoffrey Beene and Cristobal Balenciaga. Rucci even addressed some current trends, via a simple dress covered with stacks of rouged-up mousseline ruffles, a pin-tucked suede skirt, and lots of fur accessories. But he did it all with such acute attention to detail as to transcend any sense of passing whim. (It takes commitment to perfectly tailor a pair of trousers from Russian broadtail or to insert sections of lambskin into the curves of a brown wool-crepe dress without creating a bump or buckle.) And in the case of a waist-length clutch jacket covered with gently wafting guinea hen feathers, the result was a tour de force.