Abraham Lincoln: Speeches and Writings, Vol. I: 1832-1858, Vol. II: 1859-1865, edited by Don E. Fehrenbacher, (Library of America, 1989). One of the United States's two greatest presidents, Lincoln has not had a great biography written about him. This fine, comprehensive collection portrays him and his ideas clearly - in his own words.
George Washington, by Henry Cabot Lodge, (American Statesmen Series, Houghton Mifflin, 1898). Washington is more fortunate than Lincoln: He is the subject of several splendid studies. Lodge, who himself went on to a distinguished political career, helps readers see in this fine two-volume biography just how immense the first president's contributions were.
Cincinnatus: George Washington & The Enlightenment, by Gary Wills (Doubleday, 1984). Perhaps the best extant interpretation of Washington's ideas, style of leadership, and huge role in establishing American nationhood. Wills's book shows the clarity of purpose and moral force underlying the first president's leadership.
The Promise of American Life, by Herbert Croly (Northeastern University Press, 1989; first published by Macmillan in 1909). Croly, the great Progressive journalist and founder of the New Republic, writes brilliantly on American political ideas and those who framed them. His discussions of the ideas of three presidents - Lincoln, Jefferson, and Theodore Roosevelt - are superb.
The President: Office and Powers, 1787-1984, by Edward S. Corwin, edited by Randall W. Bland, et al. (New York University Press, 1984; first published 1940). The classic study of the institution of the presidency by the dean of presidential scholars, Corwin, has been revised and updated, but its essential design is maintained.
The American Presidency: An Interpretation, by Harold J. Laski (Harper Brothers, 1940). The distinguished British political theorist is part of a long line of foreign observers who have seen American institutions with clarity and insight. His book is especially valuable for its comparisons of the office of the president with that of the British prime minister.
Presidential Power and the Modern Presidents: The Politics of Leadership from Roosevelt to Reagan, by Richard E. Neustadt (The Free Press/Macmillan, 1990, first published by John Wiley & Sons, 1960). This penetrating examination of the sources and exercise of presidential power in the modern era is by a scholar who was an aide to President Truman. Neustadt shows that presidential power is persuasion far more than it is command.
Before the Fall: An Inside View of the Pre-Watergate White House, by William Safire (Doubleday, 1975 cloth; Da Capo, 1988, paper). Safire's is still the best "I was there" account of the workings of an American presidency, this of the Nixon administration before Watergate.