In May 1861, barely three weeks after the start of the Civil War, Mary Todd Lincoln received a letter from Helen Rauschnabel of Rochester, N.Y., relating “a remarkable dream I had last night about Mr. Lincoln which I think has a significant meaning.” I dreamed it stormed & thunderd & lightned terribly, it seemed as tho the Heavens & Earth were coming together, but it soon ceased, still there seemed to be very dark clouds sailing thro the horison, I thought I stood pensively viewing the scene, when a man resembling Mr Lincoln appeard standing erect in the firmament with...