dorie mccullough lawson, out guest. thank you very much. >> guest: thank you. dorie mccullough lawson is the daughter of author and historian david mccullough. she graduated with a degree of history. posterity, letters of great americans to their children was her first book. for more information about the thors of books featured on encore booknotes visit us at booktv.org and click on encore booknotes. speak in his book, "water"