If you’re at all interested in design (and if you’re not, what’s wrong with you?), you know the work of Paul Rand – even if you don’t think you do.
Some of his more famous designs:
I recently came across some cool videos about Mr. Rand and his work.
Here’s one on his book design. (Sorry for the link, they won’t let you embed.)
And here’s Jobs talking about working with him (Mr. Rand designed the Next logo):