This is the first study of all the extant remains of the important Hellenistic poet and mythographer, Parthenius of Nicaea, reputed to have been Virgil's tutor in Greek and a major literary figure in his own right. A new edition of his poetic fragments, it presents the first commentary on them since the work of August Meineke (1843); it also attempts to contextualize Parthenius within the traditions of Hellenistic poetry and within the 'neoteric revolution' of late Republican Rome. It is also the first detailed study of and commentary on the extant collection of love-stories, the Erotika Pathemata, showing their roots in Hellenistic historiography, on the one hand, and their connection to the increasingly popular genre of the novel, on the other. It uses narratology to illustrate the hitherto entirely unrecognised skill and artistry with which the stories are told, and offers a close linguistic analysis of a work of prose from a singularly badly documented period. The detailed commentary considers each story in terms of structure, literary and mythological affiliations, and parallel treatments; and a new text aims to provide an improved apparatus criticus with a good number of new suggestions. The prime importance of the work is that it aims to be a comprehensive treatment of a relatively neglected and marginalized figure; and that it sets Parthenius' poetry and prose side by side to illustrate and contextualize a literary personality who was unusual in antiquity as an accomplished writer in both genres.