Actually, Practical Reporting with Ruby and Rails is an intermediate level book: it assumes some knowledge of both Ruby and Ruby on Rails. The parts of Rails particularly relevant to reporting - aggregate functions, for example - are covered, but the basics of setting up Ruby and Rails - or, for that matter, MySQL - is not.
However, I can recommend
Beginning Ruby - another Apress title - for anyone wishing to learn Ruby on Rails.
Take it easy,
David Berube