Browsing back from your Sharing Knife post - I read this book many years ago and love it to this day. It plays to my love of explaining "magic" with reason, and also with making the antagonists as compelling as the "heroes". My favorite romance plot is, "two people do something big and important,learn something about themselves and each other in the process, and oh, fall in love"; I've got to wonder if The Perilous Gard helped set the appeal of that sort of story.