This is probably another unapproved translation as zed said his book was meant for teaching python and we need substantial changes for ruby.
The other book basically translated the code from python to ruby while keeping much of the text the same I don't know if this is the case with this one.
The prose in this translation is nearly 100% identical to the Python version with the exception of a few paragraphs that have been modified to be relevant to Ruby. All of the code exercises and required libraries have been completely adapted for Ruby. In other words, Zed did all the really hard work.
The other book basically translated the code from python to ruby while keeping much of the text the same I don't know if this is the case with this one.