You might try Metaprogramming Ruby 2 by Paolo Perrotta[1] (the link has bits you can read). I haven't read number 2, just number 1, but I'd expect it's pretty much the same. It's written with the conceit of an experienced programmer taking a new hire through the language, so it may be right for you.

[1] https://www.oreilly.com/library/view/metaprogramming-ruby-2/...