2.5 stars.I had to choose the UK edition, as the cover of the US version is totally lame. Who do they think it's going to appeal to? Boys won't want to read it because it has rainbow swirls, and girls won't want to read it because it's about a smelly boy. I certainly felt stupid finishing it in Starbucks this afternoon (though I did get to sit next to the old lady with a Kindle and her iPad-wielding elderly husband again... the second time I've encountered these tech-savvy retirees).So this is a pleasant book with thoroughly delightful characters, but I have to admit that I often didn't have a very good idea of what was going on. There's something about faerie kings and magical doppelgangers and mysterious parentage and the eponymous glass that does... I'm note sure what. Something magical. It involves magnets? It's quite like Howl's Moving Castle in that way; that book also told a confusing story about very likable characters. I suss that's just Diana Wynne Jones' style -- she doesn't work to over-explain everything, allowing for the mystery in the magical to remain. This is probably more of a problem for her adult readers; kids get wrapped up in books in a different way, and the linear aspects of the plot are less important, because of course the magic colored glass is magical, like, no doy.It's better to focus on the quirky, slightly familiar characters -- the fussy gardener, the grouchy housekeeper -- which all have the same last name, Stock, which is probably DWJ's little joke, especially considering all the scattered references to A Midsummer Night's Dream. I've got a whole stack of DWJ to enjoy, but I really wish I'd encountered her as a kid, because I think that's when she was meant to be read. EDIT, SPOILERS:Oh, so I totally forgot to mention one really weird thing about this book, which requires a reveal of one of the key mysteries. Specifically, we find out that one of the main characters, a young boy, is not, in fact, the offspring of the fairy king but of a seemingly benevolent old magician, who dies on page one. The boy's mother seems to have been a bit of a problem child, sent to the magician for "looking after" by her grandmother when the girl was a teenager. Um, so basically the 60-something magician had sex with a 16-year-old (this is excused by stating she "threw herself at him," and also maybe because women can bewitch men with spells?), knocked her up, and blamed it all on fairy magic. I guess it worked! I'm totally going to file that away for future reference. Also, WTF, DWJ?