This is the sequel to Charlie and the Chocolate Factory...
...and I'm afraid I didn't like it as much, probably because what happens to Charlie and his family and Mr. Wonka is much more far-fetched. And what I enjoyed in Charlie and the Chocolate Factory was precisely that however extraordinary, everything was plausible, or at least very close to.
In this book, our eight protagonists shoot to the stars in Mr. Wonka's glass elevator, and are mistaken for terrorists by astronauts in a space shuttle. Then they have to fight monsters called Vermicious Knids (sound the K), and when they finally get back down to the Chocolate Factory, the story shifts to something totally different... but closer to the style of the first book, therefore more to my liking: Wonka-vite, the rejuvenating pills.
So yeah, it's enjoyable, but I wouldn't call it a must-read.