I am firmly on the fence with this book. I really can't make up my mind whether I liked it or not. It is certainly one of those stories that has its moments and you find yourself going along for the ride, then boom! A seemingly uncalled for show off period of space time travel of theory of light speed, that shows how clever the author is, but doesn't add to the story. 
 The basis of the story is down right ridiculous, but funny and interesting in its audacity. The main plot of the story is that someone is kidnapping people from earth, wiping their minds and training them for a invasion on earth. The invasion is doomed to fail and the leader knows this, it's all about uniting earthlings in the defence of their planet. 
 For me, the book was about 20 pages too long. I really struggled finishing off that last bit, when I had, I took nothing extra from it and wished I had finished back on page 180. 
 It was an ok read, but there are a lot better old scifi books out there compared to this, but I am glad that I got to try some Vonnegut.