On Creativity by David Bohm. I can not recommend this book enough.
To paraphrase: Intelligence is a kind of mental alertness, which is in essence a sort of perception. It is flashes of insight which are not merely a product of memory and training because in each case we have to see anew. It is an act of perception in the mind but is also of the senses, aesthetic, and emotional. It does not arise primarily out of thought.
Art as Illumination 