From the introduction by Joyce Carol Oates:

Between them, our great visionary poets of the American nineteenth century, Emily Dickinson and Walt Whitman, have come to represent the extreme, idiosyncratic poles of the American psyche. . . .

Dickinson never shied away from the great subjects of human suffering, loss, death, even madness, but her perspective was intensely private; like Rainer Maria Rilke and Gerard Manley Hopkins, she is the great poet of inwardness, of the indefinable region of the soul in which we are, in a sense, all alone.