Excellent book by Doris Kearns Goodwin on Abraham Lincoln's cabinet during the Civil War. Lincoln chose his cabinet based on capabilities rather than party affiliation or loyalty. Included in the cabient were 3 people who had run against Lincoln in the 1856 and 1860 elections.
Interesting account of the activities and relationships of past presidents to the current office holder, from Hoover to Obama. Would love to see the update thru the Trump administration.