My favorite is Witch-Wife, and you may remember "Recuerdo" and "Macdougal Street" from the NYC subway's "Poetry in Motion" series, back at the beginning when the poems were better. Her most famous, I think, are her shortest and her longest: "First Fig" and "Second Fig" on the short end and "Renascence" on the long end.
Millay was also the first woman to ever win the Pulitzer Prize for Poetry, if that kind of thing interests you. She was also known for her open marriage and bisexual bohemianism, if THAT kind of thing interests you.
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