Whoah!! This was spectacular! I had high expectation for it and it surpassed them! There was some dryer part in the middle but overall such a good book, better written than I would have thought and even quite an emotional ending which was surprising but really satisfying. The book take a lot of subject but handle them all very well. I like the science in it obviously, I even learn some stuff, and it age relatively well in the science department in some ways, a bit less in others, but having been written 35 years ago, astronomy and physics have evolve quite a bit since then. I also enjoy the social observation, the guessing on the future, which is now our reality, the vision of what a first contact and alien life could be. I didn't expect it to go this far in the "contact" part and that was a good surprise. So, I'm impress, very happy to have read it, it might not be for everybody, but I think that this is a must read for science-fiction fan. I sure did enjoy it a lot!!