Fred I. Greenstein (1930–2018) was an emeritus professor of politics at Princeton University. He is the author of several influential works, including The Hidden-Hand Presidency: Eisenhower as Leader, Leadership in the Modern Presidency, The Presidential Difference: Leadership Style from FDR to Barack Obama, Inventing the Job of President: Leadership Style from George Washington to Andrew Jackson, and Presidents and the Dissolution of the Union: Leadership Style from Polk to Lincoln. Dale Anderson is a freelance writer and editor based in Newtown, Pennsylvania. He is the author of many works in history and politics, including The Democratic Party: American’s Oldest Party and Freedom Rides: Campaign for Change. He also collaborated with Fred I. Greenstein on Presidents and the Dissolution of the Union: Leadership Style from Polk to Lincoln.