Perhaps Rand's corporate design philosophy and process could best be described in his quote:
“Should a logo be self-explanatory? It is only by association with a product, a service, a business, or a corporation that a logo takes on any real meaning. It derives its meaning and usefulness from the quality of that which it symbolizes. If a company is second rate, the logo will eventually be perceived as second rate. It is foolhardy to believe that a logo will do its job immediately, before an audience has been properly conditioned” (http://www.logodesignlove.com/all-about-paul-rand).
Paul Rand has been defined as having a "simplistic" style, though the simplicity is for good reason. According to Rand, “ideas do not need to be esoteric to be original or exciting” and that a logo “cannot survive unless it is designed with the utmost simplicity and restraint” (http://www.paul-rand.com/biography.shtml). However, the thought behind his designs is far from simplistic. Rand's largest influence was modernist philosophy, drawing from philosophers such as Roger Fry, Alfred North Whitehead, and John Dewey. He also drew from designers like Paul Cezanne and Jan Tschichold and made sure to connect their minimalist style to modernist thinking.
Paul Rand has been considered one of the best graphic designers of all time and is the author of the groundbreaking book, Thoughts on Design. Modern advertising still draws from Rand's theories on corporate design, and it is very much reflected in today's simplistic style.