The prevailing philosophical view of the verb “to be” rests on the assumption that this verb is subject to the ambiguity inherent in natural language. This volume explores the verb underlying the concept of being in ancient Greek philosophy, offering new perspectives for evaluating the coherence of that assumption. Bringing together a series of theoretical and empirical studies, the book examines the various uses and constructions of the verb εἰμί, with particular attention to philosophical discourse. The contributions consider the linguistic structure as a whole, while focusing especially on syntactic, semantic, and pragmatic-discursive aspects.