, , allan pinkerton, the famous railroad detective, sort of found of what becomes the secret service, multiple versions of all of this. there were some controversies, other people in lincoln's entourage also claim that the new different things, but it was known even in the 1860s. it was known that he had passed through something very dangerous, that i was surprised as a look more deeply into it that most people i talked to new rotatable about it. harold serving everything about it, but it wasn't really in the general knowledge. i found it somewhat uplifting, because we all know the tragic end up lincoln's presidency and of his life, but the nearness of his escape from death in 1861 allowed me to realize we got four years of an extremely consequential presidency and if we hadn't gotten those four years might very well be two countries instead of one right now. >> right. so harold, coming back to you, i'm curious, how is the research process different for this book than from your previous work? i have seen you interview newt gingrich and you got bill clinton to i guess answer written qu