my name is francis walgren, head of books and manuscripts for christies and we're bringing significant items we've handled, the acts of congress that belonged to george washington from his library, signed by him and an know an owe stateded by him in the margins. >> you say it's one of the most important things you've ever handled. why is that? put that in perspective. >> well, both based on its significance, historical significance. his own copy of the constitution. an owetating his copy, demonstrating his role, outlining it, virtually outlining his role as president, and setting the precedent for the future role of president, how it's interpreted from the constitution. >> you can see this very light bracketing in pencil. and writing that says president. involves approving or vetoing legislation, which is, of course, the president's purgative. so historically significant, we don't always handle things necessarily historically significant at that level. they might be valuable, but there will be another copy of a book. something like this is unique [ auctioning ] >>> this copy is unique.