In 1849, while traveling as an attorney on the Eighth Judicial Circuit in Illinois, Abraham Lincoln befriended Leonard Swett (1825-89), a fellow attorney sixteen years his junior. Despite this age difference, the two men built an enduring friendship that continued until Lincoln's assassination in 1865. Until now, no historian has explored Swett's life or his remarkable relationship with the sixteenth president. In this welcome volume, Robert S. Eckley provides the first biography of Swett, crafting an intimate portrait of his experiences as a loyal member of Lincoln's inner circle. Eckley chronicles Swett's early life and the part he played in Lincoln's political campaigns, including his role as an essential member of the team behind Lincoln's two nominations and elections for the presidency. Swett counseled Lincoln during the formation of his cabinet and served as an unofficial advisor and sounding board during Lincoln's time in office. Throughout his life, Swett wrote a great deal on Lincoln, and planned to write a biography about him, but Swett's death preempted the project. His eloquent and interesting writings about Lincoln are described and reproduced in this volume, some for the first time. With Lincoln's Forgotten Friend, Eckley removes Swett from the shadows of history and sheds new light on Lincoln's personal relationships and their valuable contributions to his career.