Before he grew up and became one of Washington's most respected reporters and editors, Andrew Ferguson was, of all things, a Lincoln buff. Like so many sons of Illinois before him, he hung photos of Abe on his bedroom wall, memorized the Gettysburg Address, and read himself to sleep at night with the Second Inaugural or the "Letter to Mrs. Bixby." Ferguson eventually outgrew his obsession. But decades later, his latent buffdom was reignited by a curious...