This terrific little book was my introduction to ethical philosophy in college. This is, in fact, the best way to introduce anyone to real philosophy: Present an important philosophical problem and let two very intelligent, articulate, and well-educated people of opposing views & good faith argue the merits, demerits, and difficulties inherent in a particular theory. In fairly clear and straightforward prose, Smart and Williams plunge right into the matter and hash it out with meticulous care. Smart offers a sophisticated version of Utilitarianism for our consideration. Williams draws out the implications of it and shows how Utilitarian ethics contains contradictions and potentially repellent outcomes. (Although Williams never makes it explicit in this book, he adheres to a sophisticated modern version of classical virtue ethics, a sort of refined Nicomachean ethics.)
This may not be the last word on Utilitarianism, but it is certainly one of the most intelligent and insightful. A perfect entree to ethical philosophy, that endlessly fascinating & vitally important dialogue about how we ought to live our lives.