The fashionable silhouette of any decade isn't necessarily the way everyone always dressed in that period, but rather the way we remember them as having dressed- the dominant style.  It's the visual record of history, commerce and society, combined into the image of what a majority of the population wished to present itself as being.  In the 1940s, all women didn't wear enormous shoulder pads and ankle-strap shoes, but enough actresses in Hollywood did to establish that as the style we associate with the 1940s.  In the 1920s, all young girls were not flappers with beaded dresses and bobbed hair, but the most poignant image of that era is of young women who dared society's wrath (and risked pneumonia) by assuming the fashionable role of provocateur. 
Our Basics collection this season is about the phenomenon of a single silhouette representing a decade's ten years of fashion.  It is an overview, a valentine to each period's most memorable and ultimately democratic statement of style.