London designer Brian Clarke loves fashion and admits that sometimes he finds himself dominating conversations, particularly when his enthusiasm for a cut of cloth exceeds his audience's capacity to listen. He can hold forth on men's dress shirts for hours.

When he scrutinizes a ready-to-wear shirt, Mr. Clarke first runs his fingers along the fabric -- both inside and out. With one touch, he's abuzz with praise for a white shirt by Italian company Brioni on display at Harrods in London. It's so silky it feels almost liquid and Mr. Clarke carries it toward a light to examine the fabric more closely. "This is very good cotton," he observes. "You can barely see the weave."