I just finished the first exercise in the C++ meta programming book. Then I checked what had been done before on this mailing list. Here is my solution: using namespace boost; template <bool use_ref, typename T> struct add_const_ref_impl { typedef T const & type; }; template <typename T> struct add_const_ref_impl<true, T> { typedef T type; }; template<class T> struct add_const_ref { typedef typename add_const_ref_impl<is_reference<T>::value, T>::type type; }; From Bruce Trask comes: using namespace boost; template<typename T> struct add_const_ref { typedef typename add_reference<typename add_const<T>::type>::type type; }; His solution is SO much better then mine. However, when I first saw it I thought it must be wrong because I assumed that add_const on a reference would would return a const reference. In other words, the code below would be false: bool a = is_same<add_const<int &>::type, int &>::value; However! bool "a" is true. So my question is why is "a" true? Why isn't add_const<int &>::type == int const &? Thanks, Chris