Missed the first two lectures or wish to review the main points of the lecture? Although these lectures are somewhat out of date, for the most part they are accurate.Select the Chapter audio file that you would like to listen to, below. The audio player is Quicktime, and can be downloaded free at http://www.apple.com/quicktime/download/. Use the Mac or Windows version, as appropriate. If these lectures aren't your cup of tea, then the Power Point Presentations on this website may help you more.