You call a method on an object, and it invokes the instance method defined on the class. Simple. Except when the method isn't on the class itself, because it's inherited from a superclass. Or a singleton class, mixin, or refinement. Actually, this is kind of complicated! In this talk, we'll take an inside look at Ruby method lookup. We'll start with the basics, like inherited methods, and work our way up to the cutting-edge stuff, like refinements and prepending mixins. You'll leave with a clear understanding of how it all works, and maybe with some better ideas for structuring your code!