I've been reading The Eloquent President, by Ronald C. White Jr., for the book club I'm in. I recommend it. It's a close reading of Lincoln's developing writing style, which can seem ornate today, but which was terse by nineteenth century standards. It also sheds some light on the Civil War and its controversial, carnage-laden course.
There are photographs. The one that really struck me showed Lincoln delivering his second inaugural address - with John Wilkes Booth in the background, looking on. Photo is here. Lincoln speaks in the center. According to the book, Booth is above him, hatless, to the right side of the balcony.