>>>>> "E" == Elias Athanasopoulos <elathan / phys.uoa.gr> writes: E> elathan@velka:~/src/ruby> ruby test.rb E> test.rb:7: undefined method `bar=' for Foo:Class (NoMethodError) E> Is this behaviour normal? Yes, what you want is a class *instance* variable svg% cat b.rb #!/usr/bin/ruby class A class << self attr_accessor :a end end A.a = 12 p A.a svg% svg% b.rb 12 svg% a class variable can be seen as a shared variable svg% cat b.rb #!/usr/bin/ruby class A @@a = 12 def self.a p @@a end def a p @@a end end class B < A def self.b p @@a end def b p @@a end end A.a A.new.a B.b B.new.b svg% svg% b.rb 12 12 12 12 svg% Guy Decoux