Hi group. I've found that I have to query class methods like: irb(main):001:0> class Foo irb(main):002:1> def Foo.bar irb(main):003:2> end irb(main):004:1> end => nil irb(main):005:0> Foo.singleton_methods => ["bar"] irb(main):006:0> It is interesting that a class method is actually a singleton method. I know that there are tons of posting regarding metaclasses/objects. Unfortunately, there are simply too many to read and understand all of them. So, please forgive my naive question. Here's the thing. I guess Foo is actually defined like: irb(main):001:0> Foo = Class.new => Foo irb(main):002:0> class << Foo irb(main):003:1> def Foo.bar irb(main):004:2> end irb(main):005:1> end => nil irb(main):006:0> Foo.singleton_methods => ["bar"] irb(main):007:0> Am I correct? Sincerely, Minkoo Seo