The twenty papers by Mario Esposito (1887-1975) reprinted here date from 1909 to 1961, and complete the collection of his Hiberno-Latin studies presented in the first two volumes of his papers, published in the Variorum Collected Studies Series in 1988 and 1990. The studies exemplify Esposito's assiduous work with manuscripts, as he laid the foundations of this field (and indeed seems to have given it its name) and revealed the vast extent and nature of the literature, as well as his concern over the proper identification of Irish authors and texts. These papers are preceded by bio-bibliographical studies of Esposito himself, and the publication of some surviving correspondence.