John Hay believed that "real history is told in private letters," and the more than 220 surviving letters and telegrams from his Civil War days prove that to be true. Along with Hay's personal correspondence, this work includes his surviving official letters. It also includes some of the letters Hay composed for Lincoln's signature.

John Hay believed that "real history is told in private letters," and the more than 220 surviving letters and telegrams from his Civil War days prove that to be true, showing Abraham Lincoln in action: "The Tycoon is in fine whack. I have rarely seen him more serene and busy. He is managing this war, the draft, foreign relations, and planning a reconstruction of the Union, all at once. I never knew with what tyrannous authority he rules the Cabinet, till now. The most important things he decides and there is no cavil." Along with Hay's personal correspondence, Burlingame includes his surviving official letters. Though lacking the "literary brilliance of [Hay's] personal letters," Burlingame explains, "they help flesh out the historical record." Burlingame also includes some of the letters Hay composed for Lincoln's signature, including the celebrated letter of condolence to the Widow Bixby. More than an inside glimpse of the Civil War White House, Hay's surviving correspondence provides a window on the world of nineteenth-century Washington, DC.