This paper, representing theoretical pragmatics, aims to shed new light on the workings of irony, drawing on the research from the field of pragmatics, cognitive linguistics, and the philosophy of language. To meet this objective, the present article takes as its departure point the Gricean (1989a [1975], 1989b [1978]) philosophy, which is endorsed as a tenable basis for a new approach to irony, as long as a number of modifications and extensions are added to Grice's original assumptions. Consequently, a number of salient subtypes of irony are elucidated: propositional negation irony, ideational reversal irony (both of which embrace litotic irony and hyperbolic irony), verisimilar irony and surrealistic irony. It is also argued that, irrespective of its subtype, irony rests on overt (or rarely implied) untruthfulness, based on the flouting of the first maxim of Quality, and generates conversational implicature invariably carrying negative evaluation.