This book presents a collection of papers on clusivity, a newly coined term for the inclusive-exclusive distinction. Clusivity is a widespread feature familiar from descriptive grammars and frequently figuring in typological schemes and diachronic scenarios. However, no comprehensive exploration of it has been available so far. This book is intended to make the first step towards a better understanding of the inclusive-exclusive opposition, by documenting the current linguistic knowledge on the topic. The issues discussed include the categorial and paradigmatic status of the opposition, its geographical distribution, realization in free vs bound pronouns, inclusive imperatives, clusivity in the 2nd person, honorific uses of the distinction, etc. These case studies are complemented by the analysis of the opposition in American Sign Language as opposed to spoken languages. In-depth areal and family surveys of clusivity consider this opposition in Austronesian, Tibeto-Burman, central-western South American, Turkic languages, and in Mosetenan and Shuswap.