diff --git a/lib/set.rb b/lib/set.rb
index cb07037..231a45d 100644
--- a/lib/set.rb
+++ b/lib/set.rb
@@ -191,12 +191,23 @@ def replace(enum)
   end
 
   # Converts the set to an array.  The order of elements is uncertain.
+  # Sets can be converted implicitly to arrays.
   #
   #     Set[1, 2].to_a                    #=> [1, 2]
-  #     Set[1, 'c', :s].to_a              #=> [1, "c", :s]
+  #     Set[1, 'c', :s].to_ary            #=> [1, "c", :s]
+  #     [1, 2] + Set[1, 'c', :s]          #=> [1, 2, 1, "c", :s]
   def to_a
     @hash.keys
   end
+  alias to_ary to_a
+
+  # Converts the set to an array.  The order of elements is uncertain.
+  #
+  #     Set[1, 2].to_a                    #=> [1, 2]
+  #     Set[1, 'c', :s].to_a              #=> [1, "c", :s]
+  def to_ary
+    @hash.keys
+  end
 
   # Returns self if no arguments are given.  Otherwise, converts the
   # set to another with klass.new(self, *args, &block).
diff --git a/test/test_set.rb b/test/test_set.rb
index 54ef80b..88eb3b7 100644
--- a/test/test_set.rb
+++ b/test/test_set.rb
@@ -794,6 +794,11 @@ def test_reset
       assert_equal(klass.new([a]), set, klass.name)
     }
   end
+
+  def test_array_op_set
+    assert_equal([1,2,1,4,1], [1,2,1] + Set[4,1])
+    assert_equal([1,2,4], [1,2,1] | Set[4,1])
+  end
 end
 
 class TC_Enumerable < Test::Unit::TestCase