Gödel, Escher, Bach: An Eternal Golden Braid

People in the know call this book the book that can't be described in adjectives.

Language is a system of forms arranged to express meaning. Mathematical logic, computer programming languages, but also the system of neuron signalling in the brain, or the patterns of ants moving inside and around an ant hill, all are designed to form complex combinations that express something meaningful.

What is more, they can be used to form a higher level language, with a meaning on a different level. For instance, assembly language can be used to implement higher level programming languages; patterns of neuron signals can be said to express a higher-level language of brain signals; the same can be said for patterns of ant movement.

Hofstadter tries very hard to convince us that meaning can be an emergent property: that it should not surprise us that the man in Searle's Chinese room doesn't speak Chinese, while the system as a whole can.

He also dwells on languages powerful enough to express their own meaning. This leads to paradoxes; Epimenides already knew that, and for mathematical logic, ground breaking work in this area was done by Kurt Gödel.

The book has expositions and dialogues, in turn. The dialogues are very witty and a joy to read. The expositions are much harder, but they treat some stuff that is very fundamental to computer science, so at least computer science students should consider it a must read.

The author has woven many things he loves into this book, including lighthearted fiction and music and art. All of these enable him to approach Godel's theorem from different directions again and again without boring the reader - in fact being much more interesting than an ordinary explanation. By the use of puns and many more subtle mechanisms, the author makes many connections between seemingly unrelated things in our minds.

Artificial intelligence is a major theme of this book, as are computers and computer programming - and intelligence in general. Self reference and meaning recur again and again, becoming connected in our minds to the art of M.C. Escher, which sometimes almost succeeds in referring to itself in a fashion no two dimensional picture can. Read the book, there are many beautiful reproductions of art included.

A book so pedantic that some may find that the author's sole purpose was to prove to the world that he thinks he is a genius.

While one may learn many interesting things by reading through it, those who are already familiar with the subject matter find only that the author tries to capitalize on the sagacity of others in a repetitive manner. "Look what these other brilliant people have discovered! But wait, I am more clever because I used what knowledge they uncovered and carried it unimaginatively further such that the subjects could be interconnected through the use of fictional characters!!" would summarize what the book would say about itself when speaking from the author's point of view, if that makes any sense at all to anyone.

Recently a 20th anniversary edition of the book was released with a preface by the author. In summary, the preface says that the author did not correct any of the (numerous) mistakes in his book because, while acknowledging the errors, it was perfect as it was. Of course, the rest of the book is identical to the initial release.