This is another of those Vonnegut books that I read one right after the other. I believe this was the last one that I read during that time period, and it has always seemed different from his other novels, to me. It is also my favorite. It too has been challenged numerous times, although I could not find any good quotes as to why. Mainly I think it is more of the "sexual material" and "inappropriate or explicit language" type challenges. But it is also about a religion made up of lies, and how sometimes it is simply easier to believe the lies than to think about the truth, and maybe that offends some people.
Cat's Cradle is about the end of the world. This particular end of the world comes in a rather unique form, from a chemical compound that alters the natural state of water. As a result, once the compound is loose, it ends the world almost instantly. This book is also about the stupidity of humankind, and seems to imply that our demise by our own hands is inevitable, due to this stupidity. I love this book, and I re-read it in a matter of hours. It is a page-turner, and I found myself thinking about the characters during the times that I was not reading the book. Vonnegut causes you to think about all of the beliefs and assumptions that you take for granted. This is an essential service that should be provided by all great art. We should constantly be reevaluating such things, rather than following society blindly.
As Little Newt would say: "See the cat? See the cradle?"