diff --git a/include/boost/iterator/iterator_adaptors.hpp b/include/boost/iterator/iterator_adaptors.hpp
index deefa02..32f7cb1 100644
--- a/include/boost/iterator/iterator_adaptors.hpp
+++ b/include/boost/iterator/iterator_adaptors.hpp
@@ -18,7 +18,7 @@ template <class Base>
 struct downcastable : Base
 {
     typedef typename Base::final final_t;
- public:
+public:
     final_t& downcast() { return static_cast<final_t&>(*this); }
     const final_t& downcast() const { return static_cast<const final_t&>(*this); }
 };
@@ -207,6 +207,47 @@ struct reverse_iterator
     Base m_base;
 };
 
+template <class AdaptableUnaryFunction, class Base>
+struct transform_iterator
+    : iterator_adaptor<
+         transform_iterator<AdaptableUnaryFunction, Base>, 
+         typename AdaptableUnaryFunction::result_type,
+         typename AdaptableUnaryFunction::result_type, 
+         typename AdaptableUnaryFunction::result_type*, 
+         iterator_tag<readable_iterator_tag,
+                      typename traversal_category<Base>::type>, 
+         typename detail::iterator_traits<Base>::difference_type
+      >
+{
+  typedef typename AdaptableUnaryFunction::result_type value_type;
+private:
+  typedef iterator_adaptor<
+  transform_iterator<AdaptableUnaryFunction, Base>, value_type, value_type, value_type*, 
+    iterator_tag<readable_iterator_tag,
+				 typename traversal_category<Base>::type>, 
+    typename detail::iterator_traits<Base>::difference_type
+  > super;
+  
+public:
+  transform_iterator() { }
+
+  transform_iterator(const Base& x, AdaptableUnaryFunction f)
+    : m_base(x), m_f(f) { }
+
+  value_type dereference() const { return m_f(*m_base); }
+
+  template <class F2, class B2>
+  transform_iterator(const transform_iterator<F2,B2>& y)
+	: m_base(y.m_base), m_f(y.m_f) { }
+
+  Base& base() { return m_base; }
+  Base const& base() const { return m_base; }
+    
+private:
+  Base m_base;
+  AdaptableUnaryFunction m_f;
+};
+
 
 } // namespace boost
 
diff --git a/include/boost/iterator/iterator_categories.hpp b/include/boost/iterator/iterator_categories.hpp
index 62b1c31..dbfc0f9 100644
--- a/include/boost/iterator/iterator_categories.hpp
+++ b/include/boost/iterator/iterator_categories.hpp
@@ -4,6 +4,9 @@
 // "as is" without express or implied warranty, and with no claim as
 // to its suitability for any purpose.
 
+// TODO:
+//   Add separate category tag for operator[].
+
 #ifndef BOOST_ITERATOR_CATEGORIES_HPP
 #define BOOST_ITERATOR_CATEGORIES_HPP
 
@@ -21,19 +24,22 @@ namespace boost {
   // Return Type Categories
   struct readable_iterator_tag { };
   struct writable_iterator_tag { };
-  struct swappable_iterator_tag { };
-  struct mutable_lvalue_iterator_tag : 
-    virtual public writable_iterator_tag,
-    virtual public readable_iterator_tag { };
+  struct swappable_iterator_tag : 
+    virtual public readable_iterator_tag, // Not sure about this change -JGS
+    virtual public writable_iterator_tag { };
   struct constant_lvalue_iterator_tag : 
     virtual public readable_iterator_tag { };
+  struct mutable_lvalue_iterator_tag : 
+    virtual public swappable_iterator_tag,
+    virtual public constant_lvalue_iterator_tag { };
 
   // Traversal Categories
   struct input_traversal_tag { };
   struct output_traversal_tag { };
-  struct forward_traversal_tag { };
-  struct bidirectional_traversal_tag : public forward_traversal_tag { };
-  struct random_access_traversal_tag : public bidirectional_traversal_tag { };
+  struct forward_traversal_tag : virtual public input_traversal_tag, 
+    virtual public output_traversal_tag { };
+  struct bidirectional_traversal_tag : virtual public forward_traversal_tag { };
+  struct random_access_traversal_tag : virtual public bidirectional_traversal_tag { };
 
   struct error_iterator_tag { };
 
diff --git a/include/boost/iterator/new_iterator_tests.hpp b/include/boost/iterator/new_iterator_tests.hpp
new file mode 100644
index 0000000..0a60f10
--- /dev/null
+++ b/include/boost/iterator/new_iterator_tests.hpp
@@ -0,0 +1,427 @@
+#ifndef BOOST_NEW_ITERATOR_TESTS_HPP
+# define BOOST_NEW_ITERATOR_TESTS_HPP
+
+// This is meant to be the beginnings of a comprehensive, generic
+// test suite for STL concepts such as iterators and containers.
+//
+// Revision History:
+// 28 Oct 2002  Started update for new iterator categories
+//              (Jeremy Siek)
+// 28 Apr 2002  Fixed input iterator requirements.
+//              For a == b a++ == b++ is no longer required.
+//              See 24.1.1/3 for details.
+//              (Thomas Witt)
+// 08 Feb 2001  Fixed bidirectional iterator test so that
+//              --i is no longer a precondition.
+//              (Jeremy Siek)
+// 04 Feb 2001  Added lvalue test, corrected preconditions
+//              (David Abrahams)
+
+# include <iterator>
+# include <assert.h>
+# include <boost/type_traits.hpp>
+# include <boost/static_assert.hpp>
+# include <boost/concept_archetype.hpp> // for detail::dummy_constructor
+#include <boost/detail/iterator.hpp>
+#include <boost/pending/iterator_tests.hpp>
+
+namespace boost {
+
+void is_readable(readable_iterator_tag) { }
+void is_writable(writable_iterator_tag) { }
+void is_swappable(swappable_iterator_tag) { }
+void is_constant_lvalue(constant_lvalue_iterator_tag) { }
+void is_mutable_lvalue(mutable_lvalue_iterator_tag) { }
+
+// Preconditions: *i == v
+template <class Iterator, class T>
+void readable_iterator_test(const Iterator i1, T v)
+{
+  Iterator i2(i1); // Copy Constructible
+  typedef typename detail::iterator_traits<Iterator>::reference ref_t;
+  ref_t r1 = *i1;
+  ref_t r2 = *i2;
+  T v1 = r1;
+  T v2 = r2;
+  assert(v1 == v);
+  assert(v2 == v);
+  is_readable(typename return_category<Iterator>::type());
+}
+
+template <class Iterator, class T>
+void writable_iterator_test(Iterator i, T v)
+{
+  Iterator i2(i); // Copy Constructible
+  *i2 = v;
+  is_writable(typename return_category<Iterator>::type());
+}
+
+template <class Iterator>
+void swappable_iterator_test(Iterator i, Iterator j)
+{
+  Iterator i2(i), j2(j);
+  typename detail::iterator_traits<Iterator>::value_type bi = *i; bj = *j;
+  iter_swap(i2, j2);
+  typename detail::iterator_traits<Iterator>::value_type ai = *i; aj = *j;
+  assert(bi == aj && bj == ai);
+  is_swappable(typename return_category<Iterator>::type());
+}
+
+template <class Iterator, class T>
+void constant_lvalue_iterator_test(Iterator i, T v1)
+{
+  Iterator i2(i);
+  typedef typename detail::iterator_traits<Iterator>::value_type value_type;
+  typedef typename detail::iterator_traits<Iterator>::reference reference;
+  BOOST_STATIC_ASSERT((is_same<const value_type&, reference>::value));
+  const T& v2 = *i2;
+  assert(v1 == v2);
+  is_constant_lvalue(typename return_category<Iterator>::type());
+}
+
+template <class Iterator, class T>
+void mutable_lvalue_iterator_test(Iterator i, T v1, T v2)
+{
+  Iterator i2(i);
+  typedef typename detail::iterator_traits<Iterator>::value_type value_type;
+  typedef typename detail::iterator_traits<Iterator>::reference reference;
+  BOOST_STATIC_ASSERT((is_same<value_type&, reference>::value));
+  T& v3 = *i2;
+  assert(v1 == v3);
+  *i = v2;
+  T& v4 = *i2;
+  assert(v2 == v4);
+  is_mutable_lvalue(typename return_category<Iterator>::type());
+}
+
+template <class Iterator, class T>
+void forward_readable_iterator_test(Iterator i, Iterator j, T val1, T val2)
+{
+  Iterator i2;
+  Iterator i3(i);
+  i2 = i;
+  assert(i2 == i3);
+  assert(i != j);
+  assert(i2 != j);
+  readable_iterator_test(i, val1);
+  readable_iterator_test(i2, val1);
+  readable_iterator_test(i3, val1);
+
+  assert(i == i2++);
+  assert(i != ++i3);
+
+  readable_iterator_test(i2, val2);
+  readable_iterator_test(i3, val2);
+
+  readable_iterator_test(i, val1);
+}
+
+template <class Iterator, class T>
+void forward_swappable_iterator_test(Iterator i, Iterator j, T val1, T val2)
+{
+  forward_readable_iterator_test(i, j, val1, val2);
+  Iterator i2 = i;
+  ++i2;
+  swappable_iterator_test(i, i2);
+}
+
+// bidirectional
+// Preconditions: *i == v1, *++i == v2
+template <class Iterator, class T>
+void bidirectional_readable_iterator_test(Iterator i, T v1, T v2)
+{
+  Iterator j(i);
+  ++j;
+  forward_readable_iterator_test(i, j, v1, v2);
+  ++i;
+
+  Iterator i1 = i, i2 = i;
+
+  assert(i == i1--);
+  assert(i != --i2);
+
+  readable_iterator_test(i, v2);
+  readable_iterator_test(i1, v1);
+  readable_iterator_test(i2, v1);
+
+  --i;
+  assert(i == i1);
+  assert(i == i2);
+  ++i1;
+  ++i2;
+
+  readable_iterator_test(i, v1);
+  readable_iterator_test(i1, v2);
+  readable_iterator_test(i2, v2);
+}
+
+
+// random access
+// Preconditions: [i,i+N) is a valid range
+template <class Iterator, class TrueVals>
+void random_access_readable_iterator_test(Iterator i, int N, TrueVals vals)
+{
+  bidirectional_readable_iterator_test(i, vals[0], vals[1]);
+  const Iterator j = i;
+  int c;
+
+  for (c = 0; c < N-1; ++c) {
+    assert(i == j + c);
+    assert(*i == vals[c]);
+    assert(*i == j[c]);
+    assert(*i == *(j + c));
+    assert(*i == *(c + j));
+    ++i;
+    assert(i > j);
+    assert(i >= j);
+    assert(j <= i);
+    assert(j < i);
+  }
+
+  Iterator k = j + N - 1;
+  for (c = 0; c < N-1; ++c) {
+    assert(i == k - c);
+    assert(*i == vals[N - 1 - c]);
+    assert(*i == j[N - 1 - c]);
+    Iterator q = k - c; 
+    assert(*i == *q);
+    assert(i > j);
+    assert(i >= j);
+    assert(j <= i);
+    assert(j < i);
+    --i;
+  }
+}
+
+
+#if 0
+
+// Tests whether type Iterator satisfies the requirements for a
+// TrivialIterator. 
+// Preconditions: i != j, *i == val
+template <class Iterator, class T>
+void trivial_iterator_test(const Iterator i, const Iterator j, T val)
+{
+  Iterator k;
+  assert(i == i);
+  assert(j == j);
+  assert(i != j);
+#ifdef BOOST_NO_STD_ITERATOR_TRAITS
+  T v = *i;
+#else
+  typename std::iterator_traits<Iterator>::value_type v = *i;
+#endif
+  assert(v == val);
+#if 0
+  // hmm, this will give a warning for transform_iterator...  perhaps
+  // this should be separated out into a stand-alone test since there
+  // are several situations where it can't be used, like for
+  // integer_range::iterator.
+  assert(v == i->foo());
+#endif
+  k = i;
+  assert(k == k);
+  assert(k == i);
+  assert(k != j);
+  assert(*k == val);
+}
+
+
+// Preconditions: i != j
+template <class Iterator, class T>
+void mutable_trivial_iterator_test(const Iterator i, const Iterator j, T val)
+{
+  *i = val;
+  trivial_iterator_test(i, j, val);
+}
+
+
+
+
+
+template <class Iterator, class T>
+void dereference_test(Iterator i, T v1, read_write_iterator_tag)
+{
+  *i = v1;
+}
+
+
+// Preconditions: *i == v1, *++i == v2
+template <class Iterator, class T>
+void input_iterator_test(Iterator i, T v1, T v2) 
+{
+  Iterator i1(i);
+
+  assert(i == i1);
+  assert(!(i != i1));
+
+  // I can see no generic way to create an input iterator
+  // that is in the domain of== of i and != i.
+  // The following works for istream_iterator but is not
+  // guaranteed to work for arbitrary input iterators.
+  //
+  //   Iterator i2;
+  //
+  //   assert(i != i2);
+  //   assert(!(i == i2));
+
+  assert(*i1 == v1);
+  assert(*i  == v1);
+
+  // we cannot test for equivalence of (void)++i & (void)i++
+  // as i is only guaranteed to be single pass.
+  assert(*i++ == v1);
+
+  i1 = i;
+
+  assert(i == i1);
+  assert(!(i != i1));
+
+  assert(*i1 == v2);
+  assert(*i  == v2);
+
+  // i is dereferencable, so it must be incrementable.
+  ++i;
+
+  // how to test for operator-> ?
+}
+
+// how to test output iterator?
+
+
+template <bool is_pointer> struct lvalue_test
+{
+    template <class Iterator> static void check(Iterator)
+    {
+# ifndef BOOST_NO_STD_ITERATOR_TRAITS
+        typedef typename std::iterator_traits<Iterator>::reference reference;
+        typedef typename std::iterator_traits<Iterator>::value_type value_type;
+# else
+        typedef typename Iterator::reference reference;
+        typedef typename Iterator::value_type value_type;
+# endif
+        BOOST_STATIC_ASSERT(boost::is_reference<reference>::value);
+        BOOST_STATIC_ASSERT((boost::is_same<reference,value_type&>::value
+                             || boost::is_same<reference,const value_type&>::value
+            ));
+    }
+};
+
+# ifdef BOOST_NO_STD_ITERATOR_TRAITS
+template <> struct lvalue_test<true> {
+    template <class T> static void check(T) {}
+};
+#endif
+
+template <class Iterator, class T>
+void forward_iterator_test(Iterator i, T v1, T v2) 
+{
+  input_iterator_test(i, v1, v2);
+
+  Iterator i1 = i, i2 = i;
+
+  assert(i == i1++);
+  assert(i != ++i2);
+
+  trivial_iterator_test(i, i1, v1);
+  trivial_iterator_test(i, i2, v1);
+
+  ++i;
+  assert(i == i1);
+  assert(i == i2);
+  ++i1;
+  ++i2;
+
+  trivial_iterator_test(i, i1, v2);
+  trivial_iterator_test(i, i2, v2);
+
+ // borland doesn't allow non-type template parameters
+# if !defined(__BORLANDC__) || (__BORLANDC__ > 0x551)
+  lvalue_test<(boost::is_pointer<Iterator>::value)>::check(i);
+#endif
+}
+
+// Preconditions: *i == v1, *++i == v2
+template <class Iterator, class T>
+void bidirectional_iterator_test(Iterator i, T v1, T v2)
+{
+  forward_iterator_test(i, v1, v2);
+  ++i;
+
+  Iterator i1 = i, i2 = i;
+
+  assert(i == i1--);
+  assert(i != --i2);
+
+  trivial_iterator_test(i, i1, v2);
+  trivial_iterator_test(i, i2, v2);
+
+  --i;
+  assert(i == i1);
+  assert(i == i2);
+  ++i1;
+  ++i2;
+
+  trivial_iterator_test(i, i1, v1);
+  trivial_iterator_test(i, i2, v1);
+}
+
+// mutable_bidirectional_iterator_test
+
+// Preconditions: [i,i+N) is a valid range
+template <class Iterator, class TrueVals>
+void random_access_iterator_test(Iterator i, int N, TrueVals vals)
+{
+  bidirectional_iterator_test(i, vals[0], vals[1]);
+  const Iterator j = i;
+  int c;
+
+  for (c = 0; c < N-1; ++c) {
+    assert(i == j + c);
+    assert(*i == vals[c]);
+    assert(*i == j[c]);
+    assert(*i == *(j + c));
+    assert(*i == *(c + j));
+    ++i;
+    assert(i > j);
+    assert(i >= j);
+    assert(j <= i);
+    assert(j < i);
+  }
+
+  Iterator k = j + N - 1;
+  for (c = 0; c < N-1; ++c) {
+    assert(i == k - c);
+    assert(*i == vals[N - 1 - c]);
+    assert(*i == j[N - 1 - c]);
+    Iterator q = k - c; 
+    assert(*i == *q);
+    assert(i > j);
+    assert(i >= j);
+    assert(j <= i);
+    assert(j < i);
+    --i;
+  }
+}
+
+// Precondition: i != j
+template <class Iterator, class ConstIterator>
+void const_nonconst_iterator_test(Iterator i, ConstIterator j)
+{
+  assert(i != j);
+  assert(j != i);
+
+  ConstIterator k(i);
+  assert(k == i);
+  assert(i == k);
+
+  k = i;
+  assert(k == i);
+  assert(i == k);
+}
+
+#endif
+
+} // namespace boost
+
+#endif // BOOST_NEW_ITERATOR_TESTS_HPP
diff --git a/test/transform_iterator_test.cpp b/test/transform_iterator_test.cpp
new file mode 100644
index 0000000..585c236
--- /dev/null
+++ b/test/transform_iterator_test.cpp
@@ -0,0 +1,58 @@
+//  (C) Copyright Jeremy Siek 2002. Permission to copy, use, modify,
+//  sell and distribute this software is granted provided this
+//  copyright notice appears in all copies. This software is provided
+//  "as is" without express or implied warranty, and with no claim as
+//  to its suitability for any purpose.
+
+//  Revision History
+//  28 Oct 2002   Jeremy Siek
+//       Updated for new iterator adaptors.
+//  08 Mar 2001   Jeremy Siek
+//       Moved test of transform iterator into its own file. It to
+//       to be in iterator_adaptor_test.cpp.
+
+#include <boost/config.hpp>
+#include <iostream>
+#include <algorithm>
+#include <boost/iterator/iterator_adaptors.hpp>
+#include <boost/iterator/new_iterator_tests.hpp>
+#include <boost/pending/iterator_tests.hpp>
+
+struct mult_functor {
+  typedef int result_type;
+  typedef int argument_type;
+  // Functors used with transform_iterator must be
+  // DefaultConstructible, as the transform_iterator must be
+  // DefaultConstructible to satisfy the requirements for
+  // TrivialIterator.
+  mult_functor() { }
+  mult_functor(int aa) : a(aa) { }
+  int operator()(int b) const { return a * b; }
+  int a;
+};
+
+int
+main()
+{
+  const int N = 10;
+
+  // Test transform_iterator
+  {
+    int x[N], y[N];
+    for (int k = 0; k < N; ++k)
+      x[k] = k;
+    std::copy(x, x + N, y);
+    
+    for (int k2 = 0; k2 < N; ++k2)
+      x[k2] = x[k2] * 2;
+    
+    typedef boost::transform_iterator<mult_functor, int*> iter_t;
+    iter_t i(y, mult_functor(2));
+    boost::input_iterator_test(i, x[0], x[1]);
+    boost::input_iterator_test(iter_t(&y[0], mult_functor(2)), x[0], x[1]);
+    
+    boost::random_access_readable_iterator_test(i, N, x);
+  }
+  std::cout << "test successful " << std::endl;
+  return 0;
+}