ADDED: The official YSL website is extremely impressive. You can view designs going all the way back to 1962 and avant.
MORE: Robin Givhan writes:
In the 1960s and '70s, when he was at the height of his influence, he brought popular culture, a mannish swagger, sexual power and ethnic awareness to fashion. He gave women a wardrobe that spoke of confidence and authority. He didn't give them armor for the boardroom as much as he gave them the sartorial equivalent of chutzpah, tough talk and bawdiness. He gave dames and broads their costumes.
AND: I've never had any YSL clothes, but I've worn this perfume for years: