Goedel, Escher, Bach
I read it in my freshman university year, and it immediately became one of my favorite nonfiction books (and without any doubt the most beautiful nonfiction book I've ever read). GEB is a meditation on circularity, recursion and reflexivity, first in logic (Kurt Goedel's groundbreaking work on incompletness of powerful formal systems), graphic art (Maurits C. Escher's mindboggling artwork) and music (J. S. Bach's intricate organic compositions), but it quickly moves on many other topics: language and translation, signification and structure, physics, computer systems and languages, molecular biology, Zen Buddhism, and, finally, human and artificial intelligence.
Hofstadter's cerebral considerations are interwoven with dialogues between characters who seem to come right from a Lewis Carroll story. These narratives attempt to illustrate the following chapter and through puns, rhythm and linguistic acrobatics their structure gets to mirror their contents!
I remember having found its beginnings a bit dry, but my initial efforts to push the front door were quickly rewarded as soon as I reached the 2nd/3rd chapters.
The book is pretty much self-contained and does not require special knowledge of science or the arts beyond high-school level. Its tone's somewhat informal and most scientists I know of find it "cute". Beyond its apparent focus on circularity and intelligence, GEB is an ode to 'elegance', the concept of abstract beauty.
For someone with little scientific education, especially someone who tends to see science as an ugly or dry topic, GEB may be a way to reconciliation. Even 20 years after its first publication it's still as graceful and insightful.
On the other hand, those who have some knowledge of the topics explored may find it too light, and discard it as popular science without daring to look at the sheer grace of its approach. And it may infuriate artificial intelligence scientists, because Hofstadter's musings on the subject are so hopelessly out-of-date...
By the way, I had the honor to have dinner with Douglas Hofstadter himself and he's one of the most humble and nice scholars I've ever met... And still as creative (he works on "fluid concepts" applied to the aesthetics of typesetting).
(If you're into biology, after GEB I also recommend Humberto Maturana and Francisco Varela's *The Tree of Knowledge*, which pushes circularity and reflection a little further...)
(I'm sorry for the stilted language and fragmented review, I just got up and my 'English word factory' puffes and squeaks hard.)