Tris and Niko are visiting Tharios for a conference of mages. Well, Niko is there for the conference. Tris is more interested in the local glassmakers, where she runs across a journeyman glassmaker whose magic is running amok.I enjoy this book because I like Tris and Niko, and Keth, Dema, Chime, and other characters are fun to read about. However, the story suffers from too many coincidences. Tris just happens to walk by Keth's shop at exactly the right moment. Keth's globes just happen to relate to Dema's current investigation (and only that). Niko's conference just happens to be on scrying, which relates both to Keth's globes and Tris's studies.In general the Circle books are not as good as the Tortall books, but it's not a bad book and I do enjoy rereading it on occasion. Also, one of the characters in Shatterglass is a little glass dragon who purrs when you stroke her. It's practically worth reading for her alone.