Amy Gerstler has won acclaim for complex yet accessible poetry that is by turns extravagant, subversive, surreal, and playful. In her new collection, Medicine , she deploys a variety of dramatic voices, spoken by such disparate characters as Cinderella's wicked sisters, the wife of a nineteenth-century naturalist, a homicide detective, and a woman who is happily married to a bear. Their elusive collectivity suggests, but never quite defines, the floating...