In this chapter I consider in what sense acts characterized as being crimes against humanity can be reckoned to be, indeed, against humanity. The term crimes against humanity is now part of contemporary usage. Designating a class of offense under international law, it has also entered into moral and political discourse more generally. Its range and content are therefore of some interest. Since the notion of a crime that is against humanity is not transparent, it is worth inquiring whether any clear and useful meaning can be given to it.