. >> please join me in welcoming stephen kotkin. stephen is an international affairs professor. [inaudible] [applause] >> gets a particular pleasure to launch my remaining book tour at the university of pennsylvania bookstore because the university of pennsylvania faculty in this area were instrumental in helping me work out some of the in what i might call the first draft of this manuscript. i'm very grateful to them and would repay my gratitude by being here tonight and i appreciate the fact that those people helped me those professors are here tonight as well. so somebody said it's very difficult to summarize 739 pages of text in a a book taught that somebody else said when the camera starting rolling the book readers only 628 pages and it read so fast. my strategy would be to talk about a little bit what's in the book and spend most of the time on questions than answers. somebody asked me do we really need another biography of stalin and i said to them well, let's think about this for a second. the most consequential strongest dictatorship that world history has ever known.