I found that when I call boost::lexical_caststd::string() with an object that has virtual functions, it fails to dereference the virtual functions. It also cannot use an Abstract base type. Attached is example code. I think the problem is simply that the file boost/lexical_cast.hpp, on line 185 has: Target lexical_cast(Source arg) This should be Target lexical_cast(Source& arg) At least, this fixes all of my problems. John =:-> #include <iostream> #include <string> #include struct A { virtual int f() const = 0; }; struct B : A { virtual int f() const { return 1; } }; struct C : B { virtual int f() const { return 2; } }; std::ostream& operator<<(std::ostream& os, const A& a) { return os << a.f(); } int main() { C c; std::string s; std::cout << c << std::endl; //This should print 2 s = boost::lexical_caststd::string(c); std::cout << s << std::endl; //This should print 2 s = boost::lexical_cast(c); std::cout << s << std::endl; //This returns 1, not 2 //This fails because it tries to instantiate an object of type A. Why??? s = boost::lexical_cast(c); std::cout << s << std::endl; }