I haven't found a good starting point. The two main contenders I've read in non sequential order:

1. Micheal Heartl's Rails Tutorial. 2. Pragmatic Programmers Bookshelf - Agile Rails 3.2 (4th Edition)

Both are a good start but delve far too much into unit testing with the horrific RSpec. When you're learning something new, you don't want to muddle with learning a DSL on top of things.