  A modal characterization of the distinction between essential and accidental properties is taken for granted in nearly all work in analytic metaphysics in the latter half of the 20th century. Advocates of the modal characterization have included Ruth Barcan Marcus (1967) and Saul Kripke (1972/1980), among others. However, some other characterizations of the distinction (see §2) have recently gained currency. It is worth stressing here at the outset that although there is now some disagreement about how the distinction between essential and accidental properties is to be drawn, there is nevertheless some agreement about cases. Most would agree that however the distinction is drawn, it should come out that being human (or being human if existent) is an essential property of Socrates while being fond of dogs is a merely accidental property of Socrates.