Interprocedural static slicing of object-oriented programs that use parametric polymorphism and late binding requires the slicing algorithm to guess which implementations of each method may be called at each call site. This problem is well-known in the slicing community, and is mentioned in most papers that discuss slicing of object-oriented programs. We analyze the problem and present a solution to the problem based on technology from the compiler community. Our approach produces accurate results even in the face of multiple levels of polymorphism.