outcomes. he wasn't interested in sort of a situation where the input and wasn't measured in terms of the results. but he certainly wanted to make people's lives better. >> host: julian zelizer, is the presidential biography a relatively new phenomenon? did herbert hoover port chestera arthur wright presidential biographies? >> guest: looks, we've had them for over 100 years now, dating back to the late 19th century. so we've had them for many presidents. some were successful, some unsuccessful. it's really since harry truman that they take off in terms of sale and in terms of being ...