Absolutely awesome. As usual, Terry Pratchett did not disappoint. 
 Railway is coming to Discworld, continuing the industrial revolution started in previous books. It could be done quite simply, yet Pratchett manages to tie it very well with all the specifities of his universe AND an additional plotline. The writing is flawless, filled with humor, the characters complex and interesting - I liked the shift in points of view. 
 My only complaint (which isn't actually a complaint, mind you) ? That this would be the perfect book to end the series on, as we get to revisit some old places (and see some friendly faces, although some are merely mentioned). And I do not want Discworld to end. Not now. Not ever. 
 Hopefully it isn't the case. If it is... well, as I said, it would be a good end. I just don't want it to be one.