Although Ted Widmer writes evocatively of Lincoln’s emotional departure, little of the behind-the-scenes maneuvering that preceded or followed it features in his magisterial Lincoln on the Verge—a bit surprising, since the author is a former Clinton White House speechwriter. But this is not a book about politics. In a wholly original, gorgeously crafted reimagining, Mr. Widmer instead portrays Lincoln’s demanding journey as a Homeric odyssey through perilous terrain toward almost preordained immortality.