Have you wondered what is provided by a gem? What about monkey patches? Can you be sure that new changes do not conflict with old ones? We will demonstrate how to use Ruby’s built-in reflection methods to address all of these topics, building up from foundations available to every Ruby developer. • Introduction to Ruby methods for detecting available classes and methods • Detecting classes and methods made available by requiring a gem • Detecting direct modification of existing behavior (via monkey – patching) • Detecting indirect modification of existing behavior (module inclusion) • Recommendations for further exploration of the topic This live coding talk is accessible to beginners, and contains material useful for experts Building from tools like Object constants and Object const_get, it uses short examples to demonstrate discovery of details from gems, monkey- patches, and modules. I have been refining this presentation over the last few months, giving versions of it at B’more on Rails, NYC.rb, the New York Public Library, and (most recently) the DC Ruby Users’ Group (to positive reviews).