Metamagical Themas is a collection of Douglas Hofstadter's (Gödel, Escher, Bach) columns (of the same name) for Scientific American in the early 1980's.
If you enjoyed GEB I think you will really love this book. Hofstadter's favorite themes are represented here, and like GEB it is full of fascinating nuggets. But unlike in GEB Hofstadter is no longer constrained by the requirement to build a path from the starting blocks to a single central thesis. His Scientific American columns, collected, feel much more like what he really wanted to be writing.
The columns vary in quality (his comments on then-current AI projects, and on the cold war, seem of little interest today) but the best are no less than thrilling to read. Among my favorites are his columns on self-reference, language and its power to shape thought, the nature of creativity and cognition, and the genetic code. And his remarks about where AI research has to go if it is to really fulfill its charter of implementing "thinking" (here spelled out more explicitly than in GEB) are still relevant today.
Metamagical Themas is at least as good as, and possibly even better than, GEB. Recommended.