What type of book is Team Of Rivals?

Team of Rivals: The Political Genius of Abraham Lincoln is a 2005 book by American author Doris Kearns Goodwin that chronicles the relationship between President Abraham Lincoln and his close circle of political rivals, including William H. Seward, Salmon P. Chase, and Edward Bates. The book examines how Lincoln was able to successfully bring together a group of politically opposed men and form a "team of rivals" that ultimately led to the preservation of the Union during the American Civil War.