Reddit reviews Lincoln's Men: The President and His Private Secretaries

Ellsworth was a pal of Lincoln's and an expert recruiter and organiser of troops. In the early days of the war, there was so little standing army that whoever could raise and provide a regiment generally got to lead it. It's one of the reasons Nathan Bedford Forrest went from private to general so quickly. People who know Forrest's reputation but not his history will assume it was due to skill, but it's really because he hated taking orders from others, and quit to form his own unit. He was an incredible leader but that "only man to rise so far" is a misinterpretation of the truth.

Even though he's not the main focus of the book, he features very prominently in the first few chapters of Lincoln's Men, which is a great read. Ellsworth's impact has gotten lost to history, which now just emphasises his demise. The anecdotes there changed my view of Ellsworth from a silly gloryhound to a genuinely charismatic military leader. You understand why his death was important to Lincoln and the country.