GEB alternates dialogues and essays on the author's staggering range of fixations and obsessions in which Hofstadter adds his own remarkable insights and comparisons on topics including music, art, mathematics, genetics and philosophy. GEB's sprawling nature follows tangled paths but eventually loops back to the question of intelligence, souls, free will and self-awareness.
The unorthodox structure is what sets the book apart, but the braiding of ideas may lead to a takeaway of: "Ok, that's interesting, and you're clever, but what is the chief takeaway here?"
This is a common criticism which led led Hofstadter to author the psuedo-sequel "I Am a Strange Loop" (which I haven't read), in which he distills his arguments more directly and concisely (and personally -- he imagines a low-resolution "simulation" of his wife's mind within his own after her death).
Anyone who completes GEB comes away with an honorary computer science degree, as there's a heavy focus on computability theory, data and data structures, natural language processing, AI, recursion, memory, hardware, software, all under the guise of philosophy and investigating what gives rise to self-awareness and intelligence.
On top of this, the GEB reader receives an introduction to the art of Escher, Magritte, Bach, John Cage, as well as some basics of neuroscience, boolean logic, zen philosophy, number theory, music theory and molecular biology.
Although the number theory and biology chapters dragged, I was fascinated by the discussion of the Goedel incompleteness proof and the implications it had for the mathematics community at the turn of the century. There is also a fascinating section on AI that starts with Turing tests and pattern recognition and ends with the remarkable conclusion that a truly AI may be terrible at all the things that people may struggle with as well, such as rapid computation or chess playing.
At the least, GEB presents a multitude of ideas and food for thought. At its best, it instills lucid notions of how our minds work and what gives rise to life, language and intelligence.