This monograph is a corpus-based description of the modal system of epistolary Old Babylonian, one of the best attested Akkadian dialects, using the European structural method. The study strives to match a concrete exponent (i.e., an array of formal features, morphological and syntactic) with a semantic value, in using syntactic criteria. The book treats: 1. the asseverative paradigm (used for insistence, concession and oath), explaining the syntactic mechanism behind these forms; 2. the various precative-based paradigms in various syntactic conditions: the directive group, the wish group and the interrogative group; 3. the same forms occurring in special syntactic patterns-the sequential precative and the concessive-conditional precative; 4. the paratactic conditional; and 5. the modal nominal syntagm sa para:sim. Together with this description, some additional problems are addressed for which solutions are developed: the focus system of Old Babylonian; the general linguistic issue of "emphatic assertion" (using an English corpus); and a way to describe the syntactic nature of paratactic conditional structures.