I finished reading "Lincoln at Peoria: The Turning Point" by Lewis E. Lehrman
It describes the pivotal moment in Lincoln's career, when he emerges from the chrysalis of a backwoods lawyer and county-seat politician to become a statesman and an orator for the cause of freedom. It took a while to read (30 minutes at a time on a 3.5" phone screen), but probably best digested that way