Tense and aspect are means by which language refers to time—how an event takes place in the past, present, or future. They play a key role in understanding the grammar and structure of all languages, and interest in them reaches across linguistics. This publication is a comprehensive guide to the topics and theories that currently form the front line of research into tense, aspect, and related areas. It contains thirty-six articles, written by experts in theoretical linguistics, and is divided into six sections that cover: contexts, perspectives, tense, aspect, aspect and diathesis, and modality.