I have said that death is the irreversible breakdown of the organism as a whole. And I've now made a number of further claims about death, and some of its relations to biology, to life and to existence all of which, I hope, are consistent with the first claim. Is this first claim a definition? We can ask, what, in general, is a definition? And what, in particular, is a definition of death? Only a few of the philosophers writing on death consider these sorts of questions. Several of these writers are concerned principally with matters concerning value. They often seem to think we know well enough what death is, and are unconcerned to give a definition. Others, focusing on some of the more technical issues about human death, speak often, and confidently, about the definition of death. But only rarely have they thought much about what a definition would be. One of a handful of exceptions is Fred Feldman. In the opening chapters of Confrontations with the Reaper (1992), Feldman considers these questions in both detail and depth. I want to attend to two aspects of his discussion in particular: his distinction between an analysis and a criterion; and his attempt to define death. Alongside this, I shall take into account also the endeavours of certain other writers. Their suggestions will help throw further light on what death is.