For this volume David Wiggins has selected and revised eleven of his essays in an area of metaphysics where his work has been particularly influential, and he has added a substantial introduction and one new unpublished essay. Among the subjects treated are substance, identity, persistence, persons, sortals, and artefacts. After four and a half decades of thought [Wiggins] is still searching for satisfactory answers to the questions that obsess him, and though there is no denying the difficulties his writings sometimes present the reader, we should join him in his search and be grateful that he is still continuing, after more than forty years, to contribute to discussion of these topics on which his past writings have been so influential.