The theme of this thesis is the use of rogue characters and picaresque conventions in fiction relating to Ireland in the period from 1660 to 1790. The thesis provides an account of how a tradition of prose fiction concerning Irish criminals was shaped into an Irish novel in the eighteenth century. The picaresque has often been highlighted as an influence upon the beginnings of the Irish novel. My thesis builds on recent scholarly work which has expanded the corpus of seventeenth- and eighteenth-century Irish fiction, investigating how this body of writing responded to the example of the picaresque. The picaresque is not interpreted here as an a historical genre but as an adaptable set of conventions, Spanish in origin, which combined with English criminal literature in the seventeenth century. The first two chapters examine a little-read group of fictions which, it is argued, constitute an essential subtext for the Irish novel. Chapter I focuses upon Richard Head's The English Rogue (1665-71), and Chapter 11 analyses narratives about Irish criminals published between 1680 and 1750. This body of texts construct the Irish rogue as a protean, mobile figure with the capacity to embody a range of classes and peoples. The narrative of rogue mobility is exploited by Irish novelists after 1750, as Chapters Ill, IV and V demonstrate with readings of novels by William Chaigneau, Thomas Amory, and Charles Johnston respectively. Their novels recast stock representations of the Irish current at the time. It is argued that in the decades between 1750 and 1790, the Irish rogue narrative becomes national in its scope, and able to represent the complexities of eighteenth-century Irish culture and history.