The Works and Days (Greek: Ἔργα καὶ Ἡμέραι, Erga kai Hēmerai) is a poem in 828 hexametres by Hesiod, who may have lived around 700 BC. It is addressed to the poet's brother Perses, urging him to reconcile their quarrel, and invoking a number of myths to illustrate the need to act justly. Hesiod goes on to advise Perses on how to work as a farmer. The Works and Days of the title are the activities of the farming year and the auspicious days on which to perform them, invoked in a sort of verse almanac in the final two thirds of the poem.
Free online texts
Gutenberg: Hesiod, the Homeric Hymns, and Homerica.
History of Ancient Greece: Oligarchs and Hesiod, podcast by Ryan Stitt.
Internet Archive: The Successors of Homer, by William Cranston Lawton (1898). Multiple formats.
Librivox: Works and Days, The Theogony, and The Shield of Heracles - Public domain audiobook.
Literature and History: Hesiod's Lands and Seasons - The Works and Days of Hesiod. Podcast and transcript.
Wikipedia: Works and Days.
The Great Conversation: Further reading at Tom's Learning Notes