The Argonautica (Greek: Αργοναυτικά) is an epic poem by Apollonius of Rhodes, a Hellenistic Greek writer of the third century BCE, centring on Jason's voyage in search of the Golden Fleece. It was the most substantial epic composed between the work of Homer and Virgil, and the first to employ love as a central theme, in the form of Medea's elopement with Jason.
Free online texts
Gutenberg: The Argonautica, translated by R. C. Seaton. Multiple formats.
Internet Archive: The Argonautica. Bilingual Loeb edition, Greek and facing English translation by R. C. Seaton. Multiple formats.
University of Adelaide (Internet Archive): The Argonautica, translated by R.C. Seaton. Multiple formats.
Wikisource: Αργοναυτικά - Greek text. HTML and other formats.
Librivox: The Argonautica - public domain audiobook.
Literature and History: The Epic Anti-Hero - Apollonius' Argonautica, Books 1-2. Podcast and transcript by Doug Metzger.
Literature and History: Medea and the Argonauts - Apollonius' Argonautica, Books 3-4. Podcast and transcript by Doug Metzger.
The Great Conversation: Further reading at Tom's Learning Notes
Callimachus - traditionally seen as Apollonius's rival, advocating short poems rather than epics.
Valerius Flaccus - Argonautica - A Latin version.
Ancient Greek resources: Learn to read Greek classics in the original.