Andrew Marvell (1621–1678), the satirist and metaphysical poet, is probably most famous for such work as “To His Coy Mistress,” the best-known carpe-diem poem in English, together with “The Mower against Gardens” and “An Horatian Ode upon Cromwell’s Return from Ireland.” “The Fair Singer” is a lesser known but lovely example of a poetic conceit. In three six-line pentameter stanzas, rhymed ababcc, Marvell argues that he might have been able to withstand the allure of a singer’s eyes, and he might have been able to hold out against her beautiful voice, but the combination leaves him undone — made her slave.