I'm not a Rails dev, and I admittedly never made it all the way through this book (more out of lack of time than lack of interest, though), but I was very impressed with the first few chapters of http://ruby.railstutorial.org/ruby-on-rails-tutorial-book

It manages to cover material fairly quickly and talk you through getting a working webapp up and running (and deployed!) while still taking the time to explain the little things that a more experienced dev might find obvious.