Attributes.rb

class Book
  attr_accessor :title
  attr_reader :isbn
  attr_writer :owner
end

# This is identical to

class Book
  
  def title=(args)
    @title=args
  end
  
  def title
    @title
  end
  
  def isbn
    @isbn
  end
  
  def owner=(args)
    @owner=args
  end

end