Lincoln by Gore Vidal
Vidal's Lincoln is one of the great historical novels, as well as a great story of DC under siege. The South is seceding, construction on the Washington Memorial has stopped, and a rail-splitting lawyer from Illinois is the one holding it all together. Vidal gives us the enigmatic Lincoln through the eyes of his secretary, John Hay; his Secretary of State, William H. Seward; and a conspirator in an assassination plot, among others. Vidal's saber-like wit spares no one, even as he indelibly renders the better angels of our leaders' natures.