Since Heather McHugh first began publishing her poems in 1968, poetry readers have marveled at the immensity and range of her gift. There seems to be nothing that McHugh can't do with words and do with high wit and sonic brilliance. In her chapbook Feeler, McHugh takes on the fraught subject of empathy--how much we feel, and do, for the afflicted. It also addresses the relation between thought and feeling: "Nowadays I cannot tell/ the two apart:...