Demon of Undoing is many things. It's a SF book masquerading as fantasy, a book about the conflicts of honor and desire, a book about Law and Chaos, a book about best friends. _Demon_ has so many memorable lines and scenes that I can't possibly list even a fraction of them here.
When I picked up this book in a convinience store, I had no idea I would end up reading it 18 times (so far.) I emphasized with the semi-pariah Fenobar; I loved the Imirkairans' fear and loathing of the 'Demon,' human space colonist Sig. I drank in the legend of their quest to bring the Axe of Monghan, Fenobar's tribe's totem, to safety; I smiled at the surprising humanity of the relationship between Fenobar and Sig, in a world where honor is paramount and any sign of weakness a sin.
I say the following without reserve, without hesitation: I have read many fantasy and SF books, by such famed authors as Tolkien, Donaldson, Jordan, Asimov, Heinlein, and Dick; _Demon of Undoing_ stands equal with any of them, and is by far the most fun, most memorable, and most liked book in my sizeable collection.