A novel proposal regarding predicate-argument agreement that combines detailed empirical investigation with rigorous theoretical discussion. In this book, Omer Preminger investigates how the obligatory nature of predicate-argument agreement is enforced by the grammar. Preminger argues that an empirically adequate theory of predicate-argument agreement requires recourse to an operation, whose obligatoriness is a grammatical primitive not reducible to representational properties, but whose successful culmination is not enforced by the grammar. Preminger's argument counters contemporary approaches that find the obligatoriness of predicate-argument agreement enforced through representational means. The most prominent of these is Chomsky's “interpretability”-based proposal, in which the obligatoriness of predicate-argument agreement is enforced through derivational time bombs. Preminger presents an empirical argument against contemporary approaches that seek to derive the obligatory nature of predicate-argument agreement exclusively from derivational time bombs . He offers instead an alternative account based on the notion of obligatory operations better suited to the facts. The crucial data involves utterances that inescapably involve attempted-but-failed agreement and are nonetheless fully grammatical. Preminger combines a detailed empirical investigation of agreement phenomena in the Kichean (Mayan) languages, Zulu (Bantu), Basque, Icelandic, and French with an extensive and rigorous theoretical exploration of the far-reaching consequences of these data. The result is a novel proposal that has profound implications for the formalism that the theory of grammar uses to derive obligatory processes and properties.