it was jake viner's economic theory. and as it happened, jacob viner seated his students of a if a betically, in order to be able to remember their names. so rose director, which was her name, sat next to milton friedman. in addition, as rose always says she was the only girl in the class. >> at the time? >> at the time. >> and when did you decide to write books together? and how did you separate the responsibility? >> well, that's very hard to answer. we were married in 1938, six years ago we -- after we first met. and we had children. and rose did a wonderful job in really, taking care of the house, raising children and being an inspiration to me. but she wasn't in a position -- she had a professional career before that. she had -- written some things and worked in research organizations before that. but it wasn't until the kids were grown up and off to college that she was able, really, to spend the time working with me. so we, she -- the capitalism and freedom was based on a series of lectures that i had given at a k