"Investigating Specialized Discourse" is a shortened and revised textbook edition of the monograph "Specialized Discourse" (2003). This book analyses the various features of specialized discourse in order to assess its degree of specificity and diversification, as compared to general language. Prior to any analysis of such traits, the notion of specialized discourse and its distinctive properties are clarified. The presence of such properties is accounted for not only in linguistic but also in pragmatic terms since the approach is interpretative rather than merely descriptive. Indeed, the complexity of this discourse calls for a multidimensional analysis, covering both lexis and morpho-syntax as well as textual patterning. Some lexical aspects, morpho-syntactic features and textual genres are also examined from a diachronic perspective, thus showing how various conventions concerning specialized discourse have developed over the last centuries.