in the campus bo bombings especially in the late '60s but most of it was cocktails thrown against buildings at night with the notable exception of the one off attack that killed robinson in august of 1970 that was larger than any of the bombs set off by the other groups i am riding about. the significance cause the bomb and when i say it was a one off it was a group of students who did it one time and disappeared. >> there is a book about that. >> but the significance of that is weather was at a turning point. they were underground for eight months and trying get on their feet and the madison bombing changes the national conv conversation from what was wrong in vietnam and what was wrong with the revolutionaries on campus. i don't write a lot about campus violence but that would be the most significant bit in terms of what happened in the '70s at least. >> first, thank you so much for public enemies. it was a great read. >> thank you. >> my question is how made it clear how difficult this book was to gather information on. so what would you say was the impetus or the reason for your decision to tackle it in in the first place? what motivated you on the subject? thank