After briefly indicating in the first section how the project for this book arose and its connection with a companion work on assertion and speech acts, the Introduction articulates two fundamental assumptions of the views I’ll be advancing, which are shared by the companion work. A first assumption is that kinds like fiction and assertion have at their core a ‘natural’ kind; a second assumption is that philosophical theories like the ones advanced here have to a good extent a fictive character, which I understand by analogy with the interpretation of fiction, as that undertaking will be explained in the account on offer here. Sections ii and iii will develop these ideas. Section iv provides a brief account of the structure of the book, the topics it will cover, and how it might be read.