I have Programming Ruby, The Pragmatic Programmers' Guide, Second Edition which covers Ruby 1.8. It has been several years since I have programmed in Ruby, but I'd like to refresh my memory and bring my knowledge current.
With most programming languages, I've found that I can skip books that only concern a single version bump. Yet, Ruby is a young language and I understand there may have been significant changes in 1.9.
Although I already have the second edition, is it worthwhile to buy the third edition for Ruby 1.9? Are the differences that vast, or will it be simple enough to catch up to 1.9 with the online docs?