I sent out about 8 copies of this book to friends/relatives for christmas a couple years ago, and it was very well received. It's not without flaws, but it's absolutely packed with novel concepts, relatively short, and provides a unique experience for unsuspecting readers. The physical book cover is quite good looking as well in my opinion.
I also loved Ra by the same author, but it felt a little messier plot-wise, so I hesitate to recommend it to an audience who isn't already accustomed to reading "out-there" online/sci-fi/rationalist fiction.
I also loved Ra by the same author, but it felt a little messier plot-wise, so I hesitate to recommend it to an audience who isn't already accustomed to reading "out-there" online/sci-fi/rationalist fiction.