I'm waiting for him to announce what is the next book in the series: Garfield or McKinley.
I just read a good book on Garfield’s assasination. I forgot the title but looking just now on Amazon, I think it is Destiny of the Republic: A Tale of Madness, Medicine and the Murder of a President.
My son (11) is reading O’Reilly’s book, Killing Lincoln, which covers his last 14 days. He says it’s pretty good.