Like all of his books, this transcends just about everything else being created. Again, a book of incredible breadth, creating a world both wildly fantastical, yet eminently real. He creates worlds and characters and scenarios that are tangible, more so than any other author I can think of. The story switches back and forth between what is happening in the reality in the book and the adventures the main character Nell goes on in the Primer. But I have to say though that the ending I found the least satisfying of any book I can recall reading in quite some time.