Nearly everyone agrees that Walt Whitman is America’s greatest poet. But many Americans agree reluctantly or grudgingly and, perhaps because the influential contemporary critics of poetry—“the new critics” — have either scorned or ignored Whitman, they do not trouble to discern the true qualities of Whitman’s poetry but content themselves with admitting that in some undefined way it is “powerful.” Yet even those readers who hail Whitman’s greatness with enthusiasm and read him with ever renewed pleasure do not always find it easy to say precisely what it is about the poems that they admire. The true qualities of Emily...