In Phases of Objects, Justin Mooney argues that all objects should be treated like children: just as a child can cease to be a child without ceasing to exist when it grows into an adult, so can a clay statue cease to be a statue without ceasing to exist when it is squashed into an amorphous lump; a car can cease to be a car without ceasing to exist when it is crushed into a block of scrap metal; and a person can cease to be a person without ceasing to exist when a person dies and becomes a corpse. This view is called phasalism because it entails that these changes are changes in respect of properties called phase sortals, which are sort- or kind-properties that an object can instantiate temporarily. Mooney defends phasalism against the prevailing consensus in metaphysics by spelling out a phasalist metaphysics of material objects in great detail, highlighting its virtues, and defending it against objections. In the course of this defense, Mooney proposes a novel criterion of identity for material objects, a novel approach to solving coincidence puzzles about material objects, and a novel account of sameness relations. The final chapter draws out and defends some of the controversial consequences of phasalist metaphysics in the area of personal identity and personal ontology, focusing particularly on three important questions about human people: when does a human person begin to exist? When does a human person cease to exist? And what happens to a human person in brain transplant cases?