I used to always like those illustrations of those models, but didn't actually knew what it is all about! Until I have found some photos of the real models were it was the main reason behind those creative illustrations.
This art of illustration is called pin-up. A pin-up girl, also known as a pin-up model, is a model whose mass-roduced pictures see wide appeal as popular culture. Pin-ups are intended for informal display, e.g. meant to be "pinned-up" on a wall. Pin-up girls may be glamour models, fashion models, or actresses. [Source: Wikipedia]
Have you ever wondered about the models/idea behind those posters! I wish I could have lived when pin-up girls were the epitome of sexy! Honestly, they do represent such an elegant neat woman! Here are some photos I have found today of the real model and the illustration "poster" of her.