It's 1955, and sweaters are a big hit for fall. Worn with skirts, pants, or Bermuda shorts, most gals had at least one (or ten) in her wardrobe.
What do you wear underneath to get that true "sweater girl" look? A pointy, circle-stitched bra, of course! And if your cup size was smaller, you wore one with padding.
Here's a current fave at Couture Allure. This lambswool/fur blend twin set comes straight out of the 1950s!