Godel, Escher, Bach: an Eternal Golden Braid 
["GEB"] This is a beautiful book, one I've been reading for more than five years - and I'll probably keep reading it. Written by Douglas Hofstadter, this book won the Pulitzer prize, and catapulted him into fame. Let the author himself comment on his book. 
"I have sought to weave an Eternal Golden Braid out of these three strands: Godel, Escher, Bach. I began, intending to write an essay at the core of which would be Godel's Theorem. I imagined it would be a mere pamphlet. But my ideas expanded like a sphere, and soon touched on Bach and Escher. It took some time for me to think of making this connection explicit, instead of just letting it be a private motivating force. But finally I realized that to me, Godel and Escher and Bach were only shadows cast in different directions by some central essence. I tried to reconstruct the central object, and came up with this book." 
A short, but probably the "densest Dialogue ... in terms of formal trickery and level-play" in GEB is the Crab Canon. A few words to the uninitiated about canons. The idea of a canon is that a theme is played against itself. Complications of canons occur when the "copies" of the theme are varied in time, pitch, speed etc. A further level of complexity occurs when the theme is inverted. A crab canon is one where the theme is played backwards in time! 
You might want to look at some of Escher's drawings. In fact here's one . I would love to include Bach and Godel links too, but I'm sure 'twill be impractical and perhaps useless. 
After Martin Gardner stopped his column "Mathematical Games", in Scientific American, Hofstadter was approached to start another column. He agreed and promptly named the new column "Metamagical Themas". This column formed the basis for another book of the same name. One particularly insightful and disturbing article was A Person Paper on Purity in Language. 
Note: Most of the material in this page is drawn directly or indirectly from GEB: an EGB. If you have any comments regarding this page, please email me directly 

 Last modified March 30, 1997. Swami