 We have focused attention on one type of case that raises a puzzle about diachronic identity. Such a case involves something ostensibly becoming, or ceasing to be identical with something that is ostensibly one of its earlier or later proper parts. It would be wrong to give the impression that such a “Deon-Theon” case named after the individuals involved in the example is the only, or even main, type of case posing a problem about diachronic identity. In addition there are what are often referred to as fission and fusion cases. A fission case has the following features. We have putatively distinct things b and c existing at some later time t2. Each of b and c is related to a, which exists at an earlier time t1, in such a way that each one is ostensibly identical with a.