A team of leading philosophers presents original work on theories of parthood and of location. Topics covered include how we ought to axiomatise our mereology, whether we can reduce mereological relations to identity or to locative relations, whether Mereological Essentialism is true, different ways in which entities persist through space, time, spacetime, and even hypertime, conflicting intuitions we have about space, and what mereology and propositions can tell us about one another. The breadth and accessibility of the papers make this volume an excellent introduction for those not yet working on these topics. Further, the papers contain important contributions to these central areas of metaphysics, and thus are essential reading for anyone working in the field.