So when I bought this, I thought it was a new novel by Patricia C. Wrede, who I know from two things: the Enchanted Forest Chronicles, which are really quite good, and the junior novelization of The Phantom Menace, which... isn't. (She doesn't really get Star Wars.) So imagine my surprise when I looked at the copyright page and saw that while this edition is from last year, it was originally published back in 1984. So not so much with the new, then.
There's a lot to like in this book. Amberglas is immediately endearing, in a way that doesn't quite go with "endearing" but--her excellence as a character is immediately apparent. Of course, it's mostly from her interesting conversational style, which I must admit Wrede struggles with maintaining at times. There are two other characters with very distinctive ways of talking... one I think she also had a little trouble with, and the third I wasn't terribly fond of so I tended to skim over her dialogue's flairs.
It's also very apparent that a reread would treat the book nicely; a lot falls into place throughout the plot in a way that makes earlier things make sense, in a way that makes a reread fun with the seeing clues with hindsight et cetera. The plot also knows exactly what it wants to do, and doesn't spend a whole lot of time doing anything else--even when it looks like it is.
Another thing Wrede is good at--chapter breaks. The chapters alternate between two viewpoint characters, and once the plot gets moving pretty much every singe chapter ends at a moment of some suspense--usually in the middle of a conversation, actually, which is kind of funny when I think about it. There were times when a chapter ended and I wanted to hurry past the next one to get back to the first viewpoint, but when that chapter ended I wanted to hurry past the next one to get back to the second viewpoint, until I remembered where the first chapter had left off and wanted to resolve that again--all in all a pretty effective way to keep someone reading, at least if they have the patience and good humor to not be bothered by such transparent tension-creation.
...There's a remarkable lack of negativity here. It's not that the book was amazing and perfect; as I was reading I could tell it was an early effort from her. It's all very quick, and some things feel rushed, and some things aren't explained as well as they should be. Still, if you happen to come across it and feel like a fast light fantasy read, go for it.