The author quotes Jony Ive on simplicity. There's a great interview he did with the telegraph on simplicity: http://www.telegraph.co.uk/technology/apple/9283706/Jonathan...

My favorit quote is "Simplicity is not the absence of clutter, that's a consequence of simplicity. Simplicity is somehow essentially describing the purpose and place of an object and product. The absence of clutter is just a clutter-free product. That's not simple."