These lectures were filmed in the fall of 2012. The lectures are unscripted, unrehearsed, and unedited. Two of the original recordings were lost; these lectures have been recreated on the basis of virtually verbatim notes provided by one of the students in the course (Christopher Oppermann). As always happens in actual class situations, there are some mistakes of fact and misspoken words in the lectures. It was not possible to do retakes to correct these errors (we intend eventually to post a list of errata). The camera work, such as it is, is basically static and sometimes awkward. We hope that the spontaneity of real classroom situations compensates for the lack of studio production values in the recordings. For more information on the lectures, please listen to the preface at the beginning of the introduction.