The book’s title comes from a Harriet Tubman quotation, on the occasion of the unsuccessful assault of the all-Black 54th Massachusetts Volunteer Infantry upon the Confederate forces at Fort Wagner during the American Civil War: "We saw the lightning and that was the guns; We heard the thunder and that was the big guns; We heard the rain falling and that was the blood falling; and when we came to get in the crops, it was dead men that we reaped."